Tetradentate ligands, gold(iii) complexes, preparation method and use thereof

ABSTRACT

Provides a type of gold(III) complex supported by tetradentate ligand having a structure of formula (I). The light-emitting device prepared by using the complex as a light-emitting layer material or dopant in the light-emitting device has a high external quantum efficiency, and a low efficiency roll-off. In addition, the preparation process of the tetradentate ligand provided in the present disclosure is simple and the yield is satisfactory. More importantly, the preparation reaction of the material is controllable and stable, and has a good reproducibility, and is suitable for industrial application.

CROSS REFERENCE OF RELATED APPLICATION

This application claims the priority of Chinese Patent Application No.201910789219.7, filed on Aug. 23, 2019 and titled with “TETRADENTATELIGANDS, GOLD(III) COMPLEXES, PREPARATION METHOD AND USE THEREOF”, andthe disclosures of which are hereby incorporated by reference.

FIELD

The present invention relates to a technical field of light-emittingmaterials, in particular to a type of tetradentate ligand, a type ofgold(III) complex, and a preparation method and use thereof.

BACKGROUND

Since the advent of organic and polymer electroluminescent materials andthe corresponding devices organic light-emitting diodes (OLED), due totheir advantages such as light weight, fast response speed, low drivingvoltage, wide viewing angle, and being suitable for the manufacture offlexible substrates, a research boom has been set off in academics andindustry. These materials are also considered to be the most promisingmaterial for the next generation of flat panel display technology in thefield of commercial flat panel displays and solid-state light emittingsystems.

Among them, light-emitting materials are the key to OLED displaytechnology, and the performance of good light-emitting materials ismainly reflected in high photoluminescence quantum yield (PLQY), highelectroluminescence (EL) efficiency, high external quantum efficiency(EQE), and short radiative lifetime, low efficiency roll-off, adjustablecolor, high luminous color purity, long device operational life,suitable for CRT manufacturing process, etc., all of which mainly dependon the chemical structure of the metal complex as the light-emittingmaterial.

Metal complexes are one of the most widely studied light-emittingmaterials. This is because the presence of heavy metal centers canincrease the spin-orbit coupling efficiency of the mixed singlet andtriplet states, shorten the emission lifetime, thereby effectivelyreducing the excited state quenching due to long emission lifetime andtriplet excited state saturation and greatly improving theelectro-optical conversion efficiency. Organometallic complexes withIr(III), Ru(II), and Pt(II) as the metal centres have rich and excellentluminescent properties. Up until now, they have been studied in detail,and a series of light-emitting materials with excellent properties havebeen developed, such as porphyrin-based Pt(II) triplet luminophorePtOEP, cyclometalated Ir(III) luminophore [Ir(ppy)₃],[Ir(4,6-dFppy)₂(pic)], etc., which can be used as a dopant for themanufacture of high-efficiency OLEDs, and some have been commercialized.However, there are still major limitations in the developmentlight-emitting materials for OLEDs. This is because different metalcenters and the use of different ligand structures such as spatialconfiguration, conjugation effects, electrical properties, andsubstituent effects all will have a very substantial impact on thelight-emitting property of the metal complexes, and it is oftendifficult to accurately predict the outcome of a certain change in thechemical structure of the material. The types of heavy metal centresthat can be used for preparing metal complexes to be used in OLEDs arelimited and the cost is high. The complex structure that can be designedis diverse but the rationale of obtaining complexes having goodluminescence performance is difficult to follow, leading to difficultiesand low efficiency in discovering new light-emitting materials, narrowadjustable range of the color of the light-emitting materials, andlimited selection of commercially available light-emitting materials.Therefore, the design, reconstruction or modification of the chemicalstructure of new organometallic complexes based on different heavy metalcenters is of great significance for the discovery of new light-emittingmaterials with excellent luminescence properties, and may further reducethe manufacturing cost of the display screen.

Compared with metals such as Pt and Ir, Au is more abundant and cheaper,but the development of Au complexes as light-emitting materials is stillin the exploratory stage. Yam's group has made a lot of pioneering work[Nature Photonics, 2019, 13, 185-191; Angew. Chem. Int. Ed. 2018, 57,5463-5466; J. Am. Chem. Soc. 2017, 139, 10539-10550; J. Am. Chem. Soc.2014, 136, 17861-17868; Angew. Chem. Int. Ed. 2013, 52, 446-449; J. Am.Chem. Soc. 2010, 132, 14273-14278; U.S. Pat. No. 8,415,473; J. Am. Chem.Soc. 2007, 129, 4350-4365; Angew. Chem. Int. Ed. 2005, 44, 3107-3110;Chem. Commun. 2005, 2906-2908; J. Chem. Soc., Dalton Trans. 1993,1001-1002], which mainly relate to phosphorescence of differentgold(III) complexes supported by bidentate or tridentate ligands. Theyexplain the problem of low luminescence efficiency of Au(III) complexesusing the theory that the low-energy d-d ligand field (LF) causesserious quenching of emissive excited state, and propose to enhanceluminescence through the use of a strong σ-donor ligand in the Au(III)complexes, such as dendritic alkynyl ligands or bipolar ligandscontaining triphenylamine and benzimidazole.

Nature Photonics, 2019, 13, 185-191 newly reports a tridentate gold(III)complex. After optimization, the device fabricated with this gold(III)complex showed a maximum external quantum efficiency EQE of 21.6% and anefficiency roll-off of less than 15% at luminance of 1000 cd m². Inaddition, the EQE of the device prepared through solution process islower than 13.5%, and the current efficiency is lower than 37.4 cd A⁻¹,and the EQE drops sharply with the increase of luminance.

However, the gold complexes based on tetradentate ligand may bring aboutdifferent light-emitting properties or device performance. There is onlyone report on related research [US20170222164]. The literature describesthe palladium-catalysed intramolecular bridging of a gold(III)-boundmonodentate ligand such as alkynyl group which can provide a strongσ-donor and have a larger conjugated system or a bipolar fusedheterocyclic aryl group to the tridentate ligand of the same gold(III)complex to furnish a gold(III) complex supported by tetradentate ligand.The single-step synthesis yield is 42-72%. The maximum external quantumefficiency of the device fabricated with this kind of gold(III) complexis lower than or equal to 11.1% through solution process at a dopingconcentration of 20%, and the EQE drops sharply with the increase ofcurrent density. Although it is mentioned to have high brightness, theabsence of valid proof data renders it difficult to be used forevaluation.

The current microwave synthetic methods for the synthesis of Au(III)complexes have been employed for the preparation of bidentate ortridentate gold(III) complexes. However, the use of microwave technologyin the synthesis of gold(III) complex supported by tetradentate ligandwith gold-carbon bonds has not been reported. In 2012, Tilset andco-workers obtained bidentate gold(III) complexes by dissolving ligand2-(4-methylphenyl)pyridine and gold acetate in a mixed solvent TFA/H₂O,and reacting in a microwave reactor [Organometallics 2012, 31,6567-6571]. In 2018, the same research team obtained gold(III) complexby using 2-(3,5-di-tert-butylphenyl)pyridine as a tridentate ligand andunder the same conditions [Chem. Commun., 2018, 54, 11104-11107]. In2015, Nevado et al. obtained gold(III) complexes supported by tridentateC{circumflex over ( )}C{circumflex over ( )}N ligand by using microwavetechnology [Angew Chem. Int. Ed. 2015, 54, 14287-14290]. In 2017,Venkatesan et al. synthesized gold(III) compound supported by abidentate ligand with two C-donor atoms by oxidizing Au(I) complexes toAu(III) complexes, and then coupling the metal and the ligand throughactivation of the carbon-hydrogen C—H bond on the ligand using microwavetechnology [J. Mater. Chem. C, 2017, 5, 3765-3769]. The synthesis oftetradentate ligands has long been a challenging task. The syntheticmethod provided in the existing literature involves many steps and longoperation cycle. Through our experiments, we found that the reactionreproducibility is poor, and the yield is unstable. Moreover, thestructures of the complexes that can be developed with this method aredifficult to be modified, and many target complexes cannot besynthesized by this method, which is neither conducive to research anddevelopment, nor to commercial preparation. Because of this limitation,although the Au(III) complex supported by tetradentate ligand areexpected to have better stability as compared with the one supported bytridentate ligand, there are fewer research toward this direction, andits commercial application prospects are not promising.

In summary, although the development and research of Au complexes aslight-emitting materials in OLEDs has made preliminary progress, thereare very few cases where Au complexes meet the requirements in the priorart, and they are far from meeting the needs of light-emittingmaterials. In most products, the light-emitting performance parametersare still far from ideal. For example, the external quantum efficiencyis low, the efficiency roll-off is significant, and the external quantumefficiency cannot meet the requirements under the practical brightnessof 1000 cd m⁻². Evidently, there is a long way to go beforecommercialization. Therefore, it is of great significance to develop anew structure of ligand for preparing Au complexes with betterlight-emitting properties, especially to obtain tetradentate Au(III)complexes and with excellent properties and preparation methods.

SUMMARY

In view of this, the purpose of the present invention is to provide atype of tetradentate ligand, a type of gold(III) complex, and apreparation method and use thereof. The optical device prepared by thegold(III) complex obtained with the tetradentate ligand provided in thepresent disclosure has high external quantum efficiency and lowefficiency roll-off. Moreover, the preparation method of the gold(III)complex is simple, making it easy for realizing industrial production.

The present invention provides a type of gold(III) complex supported bytetradentate ligand having a structure of formula (I), comprising ametal center and a cyclometalating tetradentate ligand, wherein themetal center is +3 gold, which has four coordination sites in a squareplanar geometry, and occupied by cyclometalating tetradentate ligandclockwise or counterclockwise in the order of coordination atoms C, C,N, and C, to form a 5-5-6-membered fused ring structure comprisinggold-carbon bond (Au—C) and N donor bond (Au←N). That is, when the twoadjacent coordinating atoms in the tetradentate ligand are separated by3 linked covalent bonds (single bond or double bond), it coordinateswith gold to form a five-membered ring; when the two adjacentcoordination atoms in the tetradentate ligand are separated by 4 linkedcovalent bonds (single bond or double bond), it coordinates with gold toform a six-membered ring; and each coordinating atom is independentlylocated on a different aromatic ring of the tetradentate ligand. It isfound through experiments that the light-emitting device prepared byusing the gold(III) complex of the present invention as a material ordopant for the light-emitting layer in the light-emitting device hashigh external quantum efficiency and low efficiency roll-off, and thecomplex of the present invention also exhibits thermally activateddelayed fluorescence (TADF). Moreover, the preparation process of thetetradentate ligand provided in the present disclosure is simple and theyield is satisfactory. More importantly, the reaction for thepreparation of the material is controllable and stable, and has a goodreproducibility, and is suitable for industrial application.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a structural diagram of a light-emitting device accordingto an embodiment of the present invention;

FIG. 2 shows the absorption spectra of (a) complexes 1 and 2 and (b)complexes 5 and 6 in deoxygenated toluene (the complex concentration is2×10⁻⁵ mol/L) at room temperature in an embodiment of the presentinvention;

FIG. 3 shows the absorption spectra of (a) complex 3, (b) complex 4, (c)complex 7 and (d) complex 8 in different deoxygenated solvents (thecomplex concentration is 2×10⁻⁵ mol/L) at room temperature in anembodiment of the present invention;

FIG. 4 shows the emission spectra of (a) complexes 1-4 and (b) complexes5-8 in deoxygenated toluene (the complex concentration is 2×10⁻⁵ mol/L)at room temperature; emission spectra of (c) complex 4 indeoxygenated/aerated toluene at a concentration of 2×10−5 mol/L (theasterisk “*” indicates second order diffraction of the excitationwavelength of 380 nm) at room temperature in an embodiment of thepresent invention;

FIG. 5 shows the emission spectra of (a) complex 3, (b) complex 4, (c)complex 7 and (d) complex 8 in different deoxygenated solvents (thecomplex concentration is 2×10⁻⁵ mol/L) at room temperature in anembodiment of the present invention;

FIG. 6 shows the emission spectra of (a) complexes 1-4 and (b) complexes5-8 in PMMA thin films (with 4 wt % of Au^(III) complex) at roomtemperature in an embodiment of the present invention;

FIG. 7 shows the absorption spectrum (a) and emission spectrum (b) ofcomplex 9 in deoxygenated dichloromethane (the complex concentration is2×10⁻⁵ mol/L) at room temperature; emission spectrum (c) of complex 9 inPMMA thin films (with 4 wt % of Au^(III) complex) at room temperature inan embodiment of the present invention;

FIG. 8 shows the TGA thermograms of complexes 3 and 4, in which (a)complex 3 shows a 2 wt % weight loss at 394° C.; (b) complex 4 shows a 2wt % weight loss at 429° C. in an embodiment of the present invention;

FIG. 9 shows the performance of OLED devices prepared by using complex 4as a dopant in an embodiment of the present invention: (a) emissionspectra of the 4-based devices with different doping concentrations; (b)current density-voltage characteristics of the 4-based devices withdifferent doping concentrations; (c) luminance-voltage characteristicsof the 4-based devices with different doping concentrations; (d)EQE-luminance characteristics of OLEDs based on complex 4 with differentdoping concentrations;

FIG. 10 shows the performance of OLED devices prepared by using complex7 as an emissive dopant in an embodiment of the present invention;

FIG. 11 shows the performance of OLED devices prepared by using complex7 as an emissive dopant in an embodiment of the present invention;

FIG. 12 shows the performance of OLED devices prepared by using complex8 as an emissive dopant in an embodiment of the present invention.

FIG. 13 shows the comparison of the device performance between atetradentate gold(III) complex 4 and a tridentate gold(III) complex 6 inreference S1: a) current density-voltage curves of devices; b) ELspectra of devices; c) luminance decay against operation time.(tetra-Au-4 and tri-Au-6 refer to tetradentate gold(III)-TADF complex 4and the reported tridentate gold(III)-TADF complex 6 in reference S1,respectively. These device data were measured under our laboratoryconditions.)

DETAILED DESCRIPTION

The present invention provides a type of gold(III) complex, wherein thegold(III) complex has a chemical structure as shown in formula (I):

wherein

X¹, X², X³ are independently selected from carbon and nitrogen, and onlyone of X¹, X², X³ is nitrogen;

Y¹ is O, CR¹⁵R¹⁶ or S;

R¹-R¹⁶ are independently selected from hydrogen, deuterium, halogen,nitro, cyano, isocyano, trifluoromethyl, or independently selected fromthe following substituted or unsubstituted groups: alkyl, cycloalkyl,alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl,heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy,aryloxy, heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group,acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido ortrialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from thefollowing substituted or unsubstituted groups: alkyl, cycloalkyl,alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl,heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy,aryloxy and heteroaryloxy;

or any two adjacent or proximal groups in R¹-R¹⁸ together with thecarbon atoms they attached form a 5-15 membered ring.

In some embodiments, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹²,R¹³, R¹⁴, R¹⁵, R¹⁶ are independently selected from hydrogen, deuterium,halogen, nitro, cyano, isocyano, trifluoromethyl, or independentlyselected from the following substituted or unsubstituted groups: C₁₋₁₅alkyl, C₃₋₁₈ cycloalkyl, C₂₋₁₅ alkenyl, C₃₋₁₈ cycloalkenyl, C₂₋₁₅alkynyl, C₆₋₃₀ aryl, C₇₋₃₅ aralkyl, C₂₋₂₀ heteroalkyl, C₃₋₂₀heterocycloalkyl, C₅₋₃₀ heterocycloalkenyl, C₅₋₃₀ heteroaryl, C₆₋₃₀heteroaralkyl, C₁₋₂₀ alkoxy, C₆₋₃₀ aryloxy, C₅₋₃₀ heteroaryloxy,NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group, acylamido,sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido and trialkylsilyl;wherein R¹⁷ and R¹⁸ are independently selected from the followingsubstituted or unsubstituted groups: C₁₋₁₅ alkyl, C₃₋₁₈ cycloalkyl,C₂₋₁₅ alkenyl, C₃₋₁₈ cycloalkenyl, C₂₋₁₅ alkynyl, C₆₋₄₀ aryl, C₇₋₄₅aralkyl, C₂₋₂₀ heteroalkyl, C₃₋₂₀ heterocycloalkyl, C₅₋₃₀heterocycloalkenyl, C₅₋₃₀ heteroaryl, C₆₋₃₀ heteroaralkyl, C₁₋₂₀ alkoxy,C₆₋₃₀ aryloxy and C₅₋₃₀ heteroaryloxy.

In some embodiments, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹²,R¹³, R¹⁴, R¹⁵, R¹⁶ are independently selected from hydrogen, deuterium,halogen, nitro, cyano, isocyano, trifluoromethyl, or independentlyselected from the following substituted or unsubstituted groups: C₃₋₁₀alkyl, C₅₋₁₂ cycloalkyl, C₄₋₁₀ alkenyl, C₅₋₁₂ cycloalkenyl, C₄₋₁₀alkynyl, C₈₋₁₅ aryl, C₁₀₋₂₀ aralkyl, C₃₋₁₀ heteroalkyl, C₅₋₈heterocycloalkyl, C₆₋₁₅ heterocycloalkenyl, C₈₋₁₅ heteroaryl, C₈₋₁₅heteroaralkyl, C₃₋₁₀ alkoxy, C₁₀₋₂₀ aryloxy, C₈₋₁₅ heteroaryloxy,NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group, acylamido,sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido and trialkylsilyl;wherein R¹⁷ and R¹⁸ are independently selected from the followingsubstituted or unsubstituted groups: C₁₋₁₅ alkyl, C₃₋₁₈ cycloalkyl,C₂₋₁₅ alkenyl, C₃₋₁₈ cycloalkenyl, C₂₋₁₅ alkynyl, C₆₋₄₀ aryl, C₇₋₄₅aralkyl, C₂₋₂₀ heteroalkyl, C₃₋₂₀ heterocycloalkyl, C₅₋₃₀heterocycloalkenyl, C₅₋₃₀ heteroaryl, C₆₋₃₀ heteroaralkyl, C₁₋₂₀ alkoxy,C₆₋₃₀ aryloxy and C₅₋₃₀ heteroaryloxy.

In some embodiments, the NR¹⁷R¹⁸ is a group represented by the followingstructure or a derivative group of the group represented by thefollowing structure in which a hydrogen is substituted by one or more,same or different substituents:

wherein, Y² is O, S, CR²⁰R²¹, SiR²²R²³ or NR²⁴, R²⁰-R²⁴ areindependently selected from hydrogen, deuterium, halogen, substituted orunsubstituted C₁₋₁₅ alkyl, substituted or unsubstituted C₆₋₃₀ aryl; thesubstituents in the substituted derivative groups are halogen, C₁₋₂₀alkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ alkylthio, 5-6 membered cycloalkyl, 5-6membered heterocycloalkyl, C₆₋₃₀ aryl, C₆₋₃₀ aryloxy, C₅₋₃₀ heteroaryl,C₂₋₁₅ alkenyl, or C₂₋₁₅ alkynyl.

In some embodiments, when R¹-R²⁴ are groups containing substituents, thesubstituents on the groups are halogen, nitro, cyano, trifluoromethyl,C₁₋₂₀ alkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ alkylthio, 5-6 membered cycloalkyl, 5-6membered heterocycloalkyl, C₆₋₃₀ aryl, C₆₋₃₀ aryloxy, C₅₋₃₀ heteroaryl,C₂₋₁₅ alkenyl or C₂₋₁₅ alkynyl.

In some embodiments, when R¹-R²⁴ are groups containing substituents, thesubstituents on the groups are fluorine, chlorine, bromine, iodine,nitro, cyano, trifluoromethyl, methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl,n-heptyl, n-octyl, n-nonyl, n-decyl, methoxy, ethoxy, n-propoxy,isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy,neopentyloxy, n-hexoxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,cyclooctyl, vinyl, propenyl, butenyl, pentenyl, hexenyl, ethynyl,propynyl, butynyl, pentynyl, cyclopentenyl, cyclohexenyl, cycloheptenyl,phenyl, naphthyl, anthryl, phenanthryl, fluorenyl, phenylmethyl,phenylethyl, phenylpropyl, phenoloxy, methylphenyl, ethylphenyl,n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl,tert-butylphenyl, n-pentylphenyl, isopentylphenyl, neopentylphenyl,n-hexylphenyl, n-heptylphenyl, n-octylphenyl, n-nonylphenyl,n-decylphenyl, dimethylphenyl, diethylphenyl, di-n-propylphenyl,diisopropylphenyl, di-n-butylphenyl, diisobutylphenyl,di-tert-butylphenyl, di-n-pentylphenyl, di-isopentylphenyl,di-neo-pentylphenyl, di-n-hexylphenyl, di-n-heptylphenyl,di-n-octylphenyl, di-n-nonylphenyl, di-n-decylphenyl,diphenylaminophenyl, furyl, pyranyl, pyridyl, pyrimidinyl, thiazolyl,oxazolyl, imidazolyl, isoxazolyl, pyrrolyl, pyrazolyl, triazolyl,tetrazolyl, thienyl, furyl, pyridyl, pyrimidinyl, pyrazinyl,pyridazinyl, indolyl, quinolinyl, isoquinolinyl, quinoxalinyl,bipyridyl, acridinyl, phenanthridinyl, phenanthrolinyl, quinazolonyl,benzimidazolyl, benzofuranyl, benzothienyl, benzothiazolyl,benzoxazolyl, benzisoxazolyl, pyrrolidinyl, piperidinyl, piperazinyl,morpholinyl, or thiazinyl.

In some embodiments, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹²,R¹³, R¹⁴, R¹⁵, R¹⁶ are independently selected from hydrogen, deuterium,fluorine, chlorine, bromine, iodine, nitro, cyano, isocyano,trifluoromethyl, ester group, acyloxy, acylamido, sulfonylamino,sulfonyloxy, sulfonato, sulfonylamido, trialkylsilyl, methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl,neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, methoxy,ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy,n-pentoxy, isopentoxy, neopentyloxy, n-hexoxy, n-heptyloxy, n-octyloxy,n-nonyloxy, n-decyloxy, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, vinyl, propenyl, butenyl, pentenyl,hexenyl, ethynyl, propynyl, butynyl, pentynyl, cyclopentenyl,cyclohexenyl, cycloheptenyl, phenyl, naphthyl, anthryl, phenanthryl,fluorenyl, phenylmethyl, phenylethyl, phenylpropyl, phenoloxy,methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl,n-butylphenyl, isobutylphenyl, tert-butylphenyl, n-pentylphenyl,isopentylphenyl, neopentylphenyl, n-hexylphenyl, n-heptylphenyl,n-octylphenyl, n-nonylphenyl, n-decylphenyl, dimethylphenyl,diethylphenyl, di-n-propylphenyl, diisopropylphenyl, di-n-butylphenyl,diisobutylphenyl, di-tert-butylphenyl, di-n-pentylphenyl,di-isopentylphenyl, di-neo-pentylphenyl, di-n-hexylphenyl,di-n-heptylphenyl, di-n-octylphenyl, di-n-nonylphenyl, di-n-decylphenyl,diphenylaminophenyl, furyl, pyranyl, pyridyl, pyrimidinyl, thiazolyl,oxazolyl, imidazolyl, isoxazolyl, pyrrolyl, pyrazolyl, triazolyl,tetrazolyl, thienyl, furyl, pyridyl, pyrimidinyl, pyrazinyl,pyridazinyl, indolyl, quinolinyl, isoquinolinyl, quinoxalinyl,bipyridyl, acridinyl, phenanthridinyl, phenanthrolinyl, quinazolonyl,benzimidazolyl, benzofuranyl, benzothienyl, benzothiazolyl,benzoxazolyl, benzisoxazolyl, pyrrolidinyl, piperidinyl, piperazinyl,morpholinyl, thiazinyl and the following groups:

In some embodiments, at least one of R¹-R¹⁴ is NR¹⁷R¹⁸.

In some embodiments, R¹-R¹⁴ comprise 1-3 NR¹⁷R¹⁸ groups.

In some embodiments, at least one of R², R³, R⁶, R⁹, R¹², and R¹³ isNR¹⁷R¹⁸.

In some embodiments, R¹⁷ and R¹⁸ are independently substituted orunsubstituted alkyl, substituted or unsubstituted aryl, substituted orunsubstituted heteroaryl.

In some embodiments, R¹-R¹⁴ have 1-10, preferably 2, 3, 4, 5, or 6,groups that are not hydrogen, wherein the 1-10 groups that are nothydrogen are each independently selected from fluorine, chlorine,bromine, iodine, cyano, or are selected from the following substitutedor unsubstituted groups: alkyl, alkoxy, aryl, aryloxy, trialkylsilyl orNR¹⁷R¹⁸.

In some embodiments, the 5-15 membered ring formed from any two adjacentor proximal groups in R¹-R¹⁸ together with the carbon atoms theyattached is a 5-15 membered heteroaryl group, a 5-15 membered arylgroup, a 5-15 membered heterocyclic group, a 5-15 membered cycloalkylgroup or a 5-15 membered unsaturated cycloalkyl group; wherein theheteroatoms in the heteroaryl group and heterocyclic group areindependently selected from nitrogen, sulfur and oxygen.

In some preferred embodiments, X² is N, Y¹ is O, CR¹⁵R¹⁶ or S. InR¹-R¹⁶, the definition of R meets at least one of the following: atleast one of R⁶ and R⁷ is halogen, C₁₋₄ alkyl, C₆₋₄₀ substituted orunsubstituted aryl, C₆₋₄₀ substituted or unsubstituted aryloxy; R⁹ ishydrogen, deuterium, halogen, C₁₋₄ alkyl or C₆₋₄₀ substituted orunsubstituted aryl; R², R³, R¹², R¹³ are independently hydrogen,deuterium, halogen, C₁₋₄ alkyl, NR¹⁷R¹⁸, C₆₋₄₀ substituted orunsubstituted aryl, C₆₋₄₀ substituted or unsubstituted aryloxy; R¹⁵ andR¹⁶ are substituted or unsubstituted aryl, and R¹⁵ and R¹⁶ are connecteddirectly or through a heteroatom O, S, NR¹⁹, wherein R¹⁹ is substitutedor unsubstituted alkyl, or substituted or unsubstituted aryl.

In some other preferred embodiments, X³ is N, Y¹ is O, CR¹⁵R¹⁶ or S. InR¹-R¹⁶, the definition of R meets at least one of the following: atleast one of R⁸ and R⁹ is halogen, C₁₋₄ alkyl, C₆₋₄₀ substituted orunsubstituted aryl, C₆₋₄₀ substituted or unsubstituted aryloxy; R¹⁵ andR¹⁶ are substituted or unsubstituted aryl, and R¹⁵ and R¹⁶ are connecteddirectly or through a heteroatom O, S, NR¹⁹, wherein R¹⁹ is substitutedor unsubstituted alkyl, or substituted or unsubstituted aryl.

In some embodiments, the total number of carbon atoms in R¹-R¹⁴ orR¹-R¹⁶ is 1-80, preferably 12-60, more preferably 12-50.

In some embodiments, R¹⁷ and R¹⁸ are directly connected or connectedthrough a bridge atom to form a 5-7 membered heterocyclic ring or anaryl-fused heterocyclic ring.

In some other embodiments, NR¹⁷R¹⁸ is a group selected from

or a derivative group of these groups in which a hydrogen is substitutedby one or more, same or different substituents; wherein Y² is O, S,CR²⁰R²¹, SiR²²R²³ or NR²⁴, R²⁰-R²⁴ are hydrogen, deuterium, halogen,substituted or unsubstituted alkyl, substituted or unsubstituted aryl;wherein the substituents in the substituted derivative groups are notlimited, preferably the derivative groups are selected from halogen,nitro, cyanotrifluoromethyl, C₁₋₄ alkyl, C₁₋₄ alkoxy, C₁₋₄ alkylthio,5-6 membered cycloalkyl, 5-6 membered heterocycloalkyl, aryl, aryloxy,heteroaryl, alkenyl, alkynyl, and the substituents in the derivativegroup are independent groups or there are one or more 5-8 membered ringformed by connecting any two adjacent groups.

Specifically, some non-limiting examples of NR¹⁷R¹⁸ are shown in thefollowing structures:

In some embodiments, any one of R¹-R¹⁶ containing carbon atoms has nomore than 40 carbon atoms.

In some embodiments, any one of R¹-R¹⁶ containing no aryl has no morethan 6 carbon atoms.

In some embodiments, the gold(III) complex supported by tetradentateligand is any of the following compounds:

In some embodiments, the gold(III) complex supported by tetrdentateligand exhibits a photoluminescence quantum yield of more than 15% in atleast one medium, wherein the medium is conventional organic solvents ortransparent polymer dispersion substrates which can dissolve gold(III)complex; the conventional organic solvents are such as: toluene,dichloromethane; transparent polymer dispersion substrates such as: MCPfilm, PMMA film, etc.

In some embodiments, the gold(III) complex supported by tetradentateligand has an intra-ligand charge transfer (ILCT) luminescencecharacteristic that is perturbed by a metal or has a TADF (thermallyactivated delayed fluorescence) luminescence characteristic.

In some embodiments, the gold(III) complex supported by tetradentateligand, which is used as a light-emitting material or dopant in alight-emitting device, shows a maximum external quantum efficiency EQEof 15% or more in the fabricated device.

In some embodiments, the gold(III) complex supported by tetradentateligand, which is used as a light-emitting material or dopant in an OLEDlight-emitting device, has a low device efficiency roll-off.

In an embodiment, when the light-emitting brightness reaches 1000 cdm⁻², the efficiency roll-off of the device fabricated with the providedgold(III) complex supported by tetradentate ligand is lower than 15%. Inone embodiment, when the light-emitting brightness reaches 1000 cd m⁻²,the efficiency roll-off of the device fabricated with the providedgold(III) complex supported by tetradentate ligand is lower than 11%. Inother embodiments, when the device's brightness reaches 1000 cd m⁻², themaximum external quantum efficiency of the device fabricated with theprovided gold(III) complex as the dopant is greater than or equal to10%.

In other embodiments, the gold(III) complex supported by tetradentateligand exhibits above 40% photoluminescence quantum efficiency in atleast one medium, and at the same time has above 5×10³ s⁻¹ radiativedecay rate constant.

In other embodiments, the gold(III) complex supported by tetradentateligand independently exhibits above 25% photoluminescence quantumefficiency and above 5×10³ s⁻¹ radiative decay rate constant in at leastone organic solvents and at least one transparent polymer dispersedsubstrate films respectively.

In other embodiments, the gold(III) complex supported by tetradentateligand independently exhibits above 25% photoluminescence quantumefficiency and at the same time exhibits above 5×10⁴ s⁻¹ radiative decayrate constant in at least one organic solvent medium and at least onetransparent polymer dispersed substrate films respectively.

In other embodiments, the gold(III) complex supported by tetradentateligand exhibits above 15% maximum external quantum efficiency as alight-emitting material or dopant in a light-emitting device.

The invention also provides a method for preparing a type of gold(III)complex supported by tetradentate ligand, comprising:

reacting the tridentate gold(III) complex of formula (0-II) in a firstsolvent under microwave conditions to obtain a complex of formula (0-I);

or

performing the following steps successively:

-   -   a) reacting an organic compound of formula (0-III) with        gold(III) reagent in a second solvent containing acid under        microwave conditions to obtain an intermediate,    -   b) transferring the reaction product of step a) (i.e.,        intermediate) into a first solvent to react under microwave        conditions to obtain the gold(III) complex of formula (0-I)

wherein

X¹, X², X³ are independently selected from carbon and nitrogen, and onlyone of X¹, X², X³ is nitrogen;

X′¹, X′², X′³ are independently selected from CH and nitrogen, and onlyone of X′¹, X′², X′³ is nitrogen;

Y¹ is O, CR¹⁵R¹⁶ or S;

X_(a) is F, Cl, Br, I, OTf, OCOCF₃, OAc, OH, or NTf₂;

R¹⁵ and R¹⁶ are independently selected from hydrogen, deuterium,halogen, nitro, cyano, isocyano, trifluoromethyl, or independentlyselected from the following substituted or unsubstituted groups: alkyl,cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl,heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy,aryloxy, heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group,acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido andtrialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from thefollowing substituted or unsubstituted groups: alkyl, cycloalkyl,alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl,heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy,aryloxy and heteroaryloxy;

or any two adjacent or proximal groups in R¹-R¹⁸ together with thecarbon atoms they attached form a 5-15 membered ring; wherein the 5-15membered ring is a 5-15 membered heteroaryl group, a 5-15 membered arylgroup, a 5-15 membered heterocyclic group, a 5-15 membered cycloalkylgroup or a 5-15 membered unsaturated cycloalkyl group; wherein theheteroatoms in the heteroaryl group and heterocyclic group areindependently selected from nitrogen, sulfur and oxygen.

A, B, C, and D are independently substituted or unsubstituted aromaticrings, substituted or unsubstituted heteroaromatic rings, and when therings of A, B, C, and D contain multiple substituents, any two adjacentor proximal substituents can be linked to form a 5-15 ring; preferablyA, B, C, and D are independently substituted or unsubstituted C₆₋₄₀aromatic ring, substituted or unsubstituted C₅₋₄₀ heteroaromatic ring.

In some embodiments, when the rings of A, B, C, and D containsubstituents, these substituents are selected from: deuterium, halogen,nitro, nitroso, cyano, isocyano, trifluoromethyl, or selected from thefollowing substituted or unsubstituted groups: alkyl, heteroalkyl,cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, heterocyclyl,alkanoyl, aroyl, alkoxy, aryloxy, NR¹⁷R¹⁸, ester group, acylamino,sulfonamide, alkoxycarbonyl, aryloxycarbonyl, alkylsulfonyl orarylsulfonyl; alkylsilyl, arylsilyl, haloalkyl, arylalkyl.

In some embodiments, the production method specifically comprises:preforming an intramolecular Au—C(gold-carbon bond) coupling reactionbased on C—H (carbon-hydrogen bond) activation of a gold(III) complex offormula (0-II) in a first solvent under microwave conditions, whereinthe intramolecular Au—C coupling reaction based on C—H activation refersto an intramolecular Au—C coupling reaction comprising activation andcleavage of C—H bond before the reaction or during the reaction,

In some embodiments, the structure of formula (II) is prepared accordingto the following methods described in the literature:

reacting the organic compound of formula (0-III) with a Hg (II) reagentand a gold(III) reagent successively to obtain a gold(III) complex offormula (0-II); wherein this reaction does not require microwave.

In some other embodiments, the production method specifically comprises:a) performing an intermolecular coordination reaction based on C—Hactivation of an organic compound of formula (0-II) with gold(III)reagent in a second solvent containing acid under microwave conditionsto obtain an intermolecular coordination reaction product; b) performingone or more intramolecular Au—C coupling reaction based on C—Hactivation of the intermolecular coordination reaction product of stepa) in a first solvent under microwave conditions, wherein theintermolecular coordination reaction based on C—H activation comprisesintermolecular Au—N coordination reaction and intermolecular Au—Ccoupling reaction comprising activation and cleavage of C—H bond.

The invention also provides a method for preparing a gold(III) complex,comprising:

reacting the tridentate gold(III) complex of formula (II) with a mixtureof a first solvent under microwave conditions to obtain a complex offormula (I);

or performing the following steps successively;

-   -   a) reacting an organic compound of formula (III) with a        gold(III) reagent in a second solvent containing acid under        microwave conditions to obtain an intermediate;    -   b) transferring the intermediate of step a) into a first solvent        to react under microwave conditions to obtain the gold(III)        complex supported by tetradentate ligand of formula (I);

wherein

X¹, X², X³ are independently selected from carbon and nitrogen, and onlyone of X¹, X², X³ is nitrogen;

X′¹, X′², X′³ are independently selected from CH and nitrogen, and onlyone of X′¹, X′², X′³ is nitrogen;

Y¹ is O, CR¹⁵R¹⁶ or S;

X_(a) is F, Cl, Br, I, OTf, OCOCF₃, OAc, OH, or NTf₂;

R¹-R¹⁶ are independently selected from hydrogen, deuterium, halogen,nitro, cyano, isocyano, trifluoromethyl, or independently selected fromthe following substituted or unsubstituted groups: alkyl, cycloalkyl,alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl,heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy,aryloxy, heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group,acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido andtrialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from thefollowing substituted or unsubstituted groups: alkyl, cycloalkyl,alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl,heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy,aryloxy and heteroaryloxy;

or any two adjacent or proximal groups in R¹-R¹⁸ together with thecarbon atoms they attached form a 5-15 membered ring.

In the above preparation method provided by the present invention, theselection of each substituent is the same as the selection of thesubstituent in the aforementioned definition of ligand. In someembodiments, X_(a) is Br, Cl, OH, OCOCF₃ or OAc.

In some embodiments, the first solvent is water or a mixed solvent ofwater and one or more organic solvents selected from ACN, DMF, DMA, THFand 1,4-dioxane in any ratio, preferably a mixed solvent of water andACN in a volume ratio of water:ACN=3:1-1:3, and more preferably in avolume ratio of H₂O:ACN=1.5:1-1:1.5.

In some embodiments, the reaction temperature of the reaction performedin the first solvent (referred to as intramolecular Au—C couplingreaction in this application) is 100-170° C.

In some embodiments, the reaction time of the intramolecular Au—Ccoupling reaction is 10-100 min.

In some embodiments, the reaction temperature of the intramolecular Au—Ccoupling reaction using formula (II) as the starting material is110-130° C., and the reaction time is 10-40 min, and preferably 20-30min.

In some embodiments, the reaction temperature of the intramolecular Au—Ccoupling reaction (i.e., the reaction of step b)) using the reactionproduct of step a) (i.e., intermediate) as the starting material is120-170° C., preferably 130-150° C., the reaction time is 50-100 min,preferably 70-90 min.

In some embodiments, the molar ratio of the tridentate gold(III) complex(formula II) or intermediate to a first solvent is 10%-0.1%, preferably2%-0.5%.

In some embodiments, a step of post-treatment and purification isfurther included after the reaction; further, the step of post-treatmentand purification comprises extraction and column purification usingorganic phase/aqueous phase.

In some embodiments, the gold(III) reagent is selected from Au(OAc)₃,AuCl₃, Au(OTf)₃, HAuCl₄, KAuCl₄, NaAuCl₄, KAuBr₄ and NaAuBr₄, preferablyAu(OAc)₃.

In some embodiments, the acid in the second solvent containing acid isAcOH, TFA, TfOH, TsOH, HF, HCl, HBr.

In some embodiments, the second solvent is a mixed solvent of one ormore of water, conventional alcohol solvents, acetonitrile, DMF, DMSO,DMA, THF and 1,4-dioxane in any ratio, wherein the conventional alcoholsolvents include but are not limited to methanol, ethanol, andisopropanol.

In some embodiments, the second solvent is a mixed solvent of TFA/water,TFA/ethanol, TFA/methanol, AcOH/water, HCl/water, TFA/ethanol/water,TFA/methanol/water, TFA/ACN/water.

In some embodiments, the volume ratio of the acid in the second solventto the rest solvents is 10:1-1:10; preferably 2:1-1:2.

In some embodiments, the reaction temperature of step a) is 110-170° C.,preferably 120-140° C.

In some embodiments, the reaction time of step a) is 20-50 min.

In some embodiments, after the reaction in step a) is completed,extraction and concentration with an organic solvent are performed toobtain an intermediate; it can be directly used in the preparationreaction in step b) without further purification.

In some embodiments, the reaction of step a) further includes adding analkali metal salt of trifluoroacetic acid, such as CF₃COONa, CF₃COOK, tothe reaction system. Preferably, the addition amount of the alkali metalsalt of trifluoroacetic acid is 3-5 times of the gold(III) reagent inthe system; preferably, when the alkali metal salt of trifluoroaceticacid is added, preferably the reaction system uses AcOH/H₂O with avolume ratio of 2:1-1:2 as the second solvent.

In some embodiments, when at least one of R¹-R¹⁴ is halogen, thepreparation method of the gold(III) complex supported by tetradentateligand further includes a step of converting R group that is halogen toa non-halogen group, for example, the non-halogen group can be NR¹⁷R¹⁸.

The gold(III) complex of formula (II) of the present invention can beobtained from the organic compound of formula (III) through conventionalor documented multi-step reactions. For example, in one embodiment, themulti-step reaction successively include: the organic compound offormula (III) undergoes CH activation reaction with the participation ofHg(II) reagent to obtain ligand-Hg(II) compound, and then Au(III) andHg(II) undergo metal displacement reaction with the participation ofgold(III) reagent to obtain a gold(III) complex with tridentate ligand,wherein the Hg(II) reagent includes but not limited to HgCl₂, Hg(OAc)₂,and the gold(III) reagent includes but not limited to KAuCl₄, NaAuCl₄,HAuCl₄, Au(OAc)₃, AuCl₃, KAuBr₄, NaAuBr₄, Au(OTf)₃. In one embodiment,the multi-step reaction further includes: after the metal replacementreaction, HX_(a) or a salt form of X_(a) (for example, when X_(a) isCF₃COO, the silver salt of X_(a) is CF₃COOAg) participates in adisplacement reaction of X_(a).

In order to achieve the purpose of the present invention, the presentinvention also provides a gold(III) complex with tridentate ligandrepresented by formula (II) which can be used to prepare the structurerepresented by formula (I).

wherein Xa is F, Cl, Br, I, OTf, OCOCF₃, OAc, OH, NTf₂;

X¹-X³, Y¹, R¹-R¹⁴ are defined as described above.

In order to achieve the purpose of the present invention, the presentinvention also provides an organic compound represented by formula (III)that can be used to prepare the structure of formula (I),

wherein optionally in X′¹-X′³: one X′ is N atom, two X's are CH; Y¹,R¹-R¹⁴ are defined as described above.

In order to achieve the objective of the present invention, the presentinvention also provides use of the gold(III) complex of the presentinvention in the preparation of light-emitting devices.

In order to achieve the objective of the present invention, the presentinvention also provides a light-emitting device comprising alight-emitting layer, wherein the light-emitting layer is the gold(III)complex according to the present invention.

In order to achieve the purpose of the present invention, the presentinvention provides a light-emitting device, comprising a type ofgold(III) complex supported by tetradentate ligand represented byformula I as defined above.

In some embodiments, the light-emitting device includes: a substrate, ananode layer, a hole injection layer, a hole transport layer (HTL), anemitting layer (EML), and an electron transport layer (ETL), an electroninjection layer and a cathode layer, the gold(III) complex supported bytetradentate ligand is located in the emitting layer EML; specifically,the structure of the light-emitting device is shown in FIG. 1 . FIG. 1shows a structural diagram of a light-emitting device according to anembodiment of the present invention.

In some embodiments, the light-emitting device exhibits a maximumexternal quantum efficiency of 13-25%; preferably, in some embodiments,the light-emitting device exhibits a maximum external quantum efficiencyof 20-25%; preferably, in some embodiments, the light-emitting deviceexhibits an external quantum efficiency of greater than 20%, includingbut not limited to greater than 21%, 22%, 23%, 24%, 25%.

In some embodiments, the light-emitting device OLED has a low efficiencyroll-off; in one embodiment, when the light-emitting brightness reaches1000 cd m⁻², the efficiency roll-off is lower than 12%. In anotherembodiment, when the light-emitting brightness reaches 1000 cd m⁻², theefficiency is lower than 11%. In other embodiments, when thelight-emitting brightness reaches 1000 cd m⁻², the OLED device preparedusing the provided gold(III) complex supported by tetradentate ligand asa dopant can maintain an external quantum efficiency of 10% above.

In some embodiments, a hole-blocking layer is further included betweenthe light-emitting layer and the electron transport layer;

In some embodiments, the light-emitting layer includes one or morelayers, and the gold(III) complex supported by tetradentate ligandprovided in the present invention is located in at least one of thelight-emitting layers.

Specifically, the light-emitting layer can be prepared by vacuumevaporation, solution method or inkjet printing method to form a filmcontaining the gold(III) complex supported by tetradentate ligand.

The Technical Solution Provided in the Present Invention at LeastSatisfies at Least One of the Following:

The tetradentate ligand provided in the present invention is coordinatedwith gold(III) to form a gold(III) complex supported by tetradentateligand. The gold(III) complex is used as a light-emitting material ordopant to produce OLED light-emitting devices, showing highlight-emitting brightness and electroluminescence efficiency andexternal quantum efficiency, the measured maximum current efficiency isup to 78 cd A⁻¹, the maximum external quantum efficiency EQE isgenerally greater than 15%, up to 25%, and the EQE generally remainsabove 11% at a brightness value of 1000 cd m⁻², up to 22%, and theefficiency roll-off is reduced to 11%, and it is a new type of organiclight-emitting material potentially used in OLED.

In addition, this kind of complexes with the same core structure hasgood universality in light-emitting properties. By adjusting the typeand position of the substituents on the core ligand structure, andcombining with the use of dispersion medium with different polarities,the emitting color of the complexes can be adjusted.

The present invention provides a preparation method of a new type ofgold(III) complex supported by tetradentate ligand. The method utilizesmicrowave to promote C—H activation and intramolecular Au—C couplingreaction, and when necessary, combining with microwave-promotedintermolecular coordination coupling, can obtain the target product witha 5-5-6 rigid ring structure in a moderate to excellent yield. Thegold(III) complex supported by tetradentate ligand provided in thepresent invention and other gold(III) complexes with similar frameworkstructures all can be prepared by this method, and this methodsimplifies the synthetic method of the gold(III) complex supported bytetradentate ligand, and has simple operation and satisfactory yield.More importantly, the reaction is controllable and stable, and has agood reproducibility, and is suitable for industrial application

In other embodiments, the gold(III) complex supported by tetradentateligand exhibits above 40% of photoluminescence quantum efficiency in atleast one of the medium, and at the same time has above 5×10³ s⁻¹ ofradiative decay rate constant.

In other embodiments, the gold(III) complex supported by tetradentateligand independently exhibits above 25% of photoluminescence quantumyield and above 5×10³ s⁻¹ of radiative decay rate constant in at leastone organic solvent and at least one transparent polymer dispersedsubstrate films respectively.

In other embodiments, the gold(III) complex supported by tetradentateligand independently exhibits above 25% of photoluminescence quantumefficiency and at the same time exhibits above 5×10⁴ s⁻¹ of radiativedecay rate constant in at least one organic solvent medium and at leastone transparent polymer dispersed substrate films respectively.

In other embodiments, the gold(III) complex supported by tetradentateligand exhibits above 15% of maximum external quantum efficiency as alight-emitting material or dopant in a light-emitting device.

Definition

To facilitate the understanding of the present invention, unlessotherwise specified, some terms, abbreviations or other abbreviatedwords used herein are defined as follows.

“Alkyl”, when used alone or in combination with other groups, representsa saturated linear or branched group containing 1-12 carbon atoms, suchas methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl,pentyl, n-pentyl, n-hexyl, isohexyl, n-heptyl, n-octyl, n-decyl, etc.

“Alkenyl”, when used alone or in combination with other groups,represents a linear or branched group containing 2-12 carbon atoms andan unsaturated double bond, including linear or branched diene, forexample: vinyl, allyl, 1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl,1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl,3-hexenyl, 4-hexenyl, 5-hexenyl, 1-heptenyl, 2-heptenyl, 3-heptenyl,4-heptenyl, 5-heptenyl, 6-heptenyl, 1,3-butadiene, 1,3-pentadiene,2-methyl-1,3-butadiene, etc.

“Alkynyl”, when used alone or in combination with other groups,represents ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl,3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl,2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, linear or branched diynes ortriynes, such as 1,3-butadiyne, etc., which may be further substitutedwith aryl.

“Cycloalkyl”, when used alone or in combination with other groups,represents a 3-7 membered carbocyclic group, such as cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, etc.

“Cycloalkenyl”, when used alone or in combination with other groups,represents a 3-7 membered cyclic group containing one or more than oneunsaturated double bond, for example: cycloalkyl, 1-cyclobutenyl,2-cyclobutenyl, 1-cyclopentenyl, 2-cyclopentenyl, 3-cyclopentenyl,1,3-cyclopentadienyl, 1-cyclohexenyl, 2-cyclohexenyl, 3-cyclohexenyl,1,3-cyclohexadienyl, cycloheptenyl, cycloheptadienyl, cycloheptatrienyl,etc.

“Aryl” or “aromatic”, when used alone or in combination with othergroups, refers to an optionally substituted aromatic carbocyclic groupcontaining 1, 2 or 3 rings, which are connected by a bond or in a fusedway, for example: phenyl, biphenyl, naphthyl, tetrahydronaphthalene,dihydroindene, which can be further substituted by other aryl oraryl-containing substituents.

“Heterocyclic group” or “heterocyclic ring”, when used alone or incombination with other groups, represents an optionally substituted a3-7 membered cyclic group containing more than one heteroatom, which isselected from N, S and O. This group includes saturated, partiallysaturated and aromatic unsaturated heterocyclic groups. Saturatedheterocyclic groups are equivalent to the term “heterocycloalkyl”herein, when used alone or in combination with other groups, include thefollowing examples: aziridinyl, azetidinyl, tetrahydrofuranyl,tetrahydrothienyl, oxazolidinyl, thiazolidinyl, benzothiazolyl,pyrrolidinyl, imidazolidinyl, piperidinyl, piperazinyl, thiazinyl,2-oxopiperidinyl, 4-oxopiperidinyl, 2-oxopiperazinyl, 3-oxopiperazinyl,morpholinyl, thiomorpholinyl, 2-oxomorpholinyl, azepinyl, diazapinyl,oxapinyl, thiapinyl, etc., 1-3-oxanyl, etc. The partially saturatedheterocyclic group is equivalent to the term “heterocyclenyl” herein,when used alone or in combination with other groups, includes thefollowing examples: dihydrothienyl, dihydropyranyl, dihydrofuranyl,dihydrothiazolyl, etc. The aromatic unsaturated heterocyclic group isequivalent to the term “heteroaryl” or “heteroaromatic” herein, whenused alone or in combination with other groups, can be a monocyclicring, and can also be a bonded or fused polycyclic ring, which includesthe following examples: thiazolyl, oxazolyl, imidazolyl, isoxazolyl,pyrrolyl, pyrazolyl, triazolyl, tetrazolyl, thienyl, furyl, pyridyl,pyrimidinyl, pyrazinyl, pyridazinyl, indolyl, quinolinyl, isoquinolinyl,quinoxalinyl, bipyridyl, acridinyl, phenanthridinyl, phenanthrolinyl,quinazolonyl, benzimidazolyl, benzofuranyl, benzothienyl,benzothiazolyl, benzoxazolyl, benzisoxazolyl, bipyridyl,biphenylpyridyl.

“Heteroalkyl”, when used alone or in combination with other groups,represents a linear or branched alkyl containing more than oneheteroatom, which is selected from N, S and O.

Examples of it include: methoxymethyl, methoxyethyl, 2-methoxypropyl,dimethylaminoethyl, 2-methylthiobutyl, etc.

Herein, unless otherwise specified, “heteroalkyl” and “heterocyclicgroup” contain one or more heteroatoms, preferably 1-6, more preferably1, 2, or 3. When the groups contain multiple heteroatoms, the multipleheteroatoms may be the same or different.

“Halogen”, when used alone or in combination with other groups, such asforming “haloalkyl”, “perhaloalkyl”, etc., refers to fluorine, chlorine,bromine or iodine. The term “haloalkyl” represents alkyl as definedabove substituted by one or more halogens, including perhaloalkyl, suchas fluoromethyl, difluoromethyl, trifluoromethyl, fluoroethyl,difluoroethyl, trifluoromethyl, etc. The term “haloalkoxy” representshaloalkyl as defined above, which is directly connected to an oxygenatom, such as fluoromethoxy, chloromethoxy, fluoroethoxy, chloroethoxy,etc.

“Acyl”, when used alone or in combination with other groups, includesthe following forms: —C(═O)H, —C(═O)-alkyl, —C(═O)-aryl, —C(═O)-aralkyland —C(═O)-heteroaryl, such as formyl, acetyl, propionyl, butyryl,isobutyryl, valeryl, hexanoyl, heptanoyl, benzoyl, etc. The non-C(═O)—part in the acyl may be substituted with optional substituents,including but not limited to halogen, lower alkyl (C1-C4 alkyl), aryl oraryl-containing substituents.

“Ester” is a type of carboxylic acid derivative, when used alone or incombination with other groups, it represents the —COO— group, including:alkoxycarbonyl, such as methoxycarbonyl, ethoxycarbonyl, etc.;aryloxycarbonyl, such as phenoxycarbonyl, naphthoxycarbonyl, etc.;aralkyloxycarbonyl, such as benzyloxycarbonyl, phenethoxycarbonyl,naphthylmethoxycarbonyl; heterocyclyloxycarbonyl, wherein heterocyclylis defined as above; the non-COO— part of the ester group may be furthersubstituted with optional substituents.

“Acyloxy”, when used alone or in combination with other groups, meansthat acyl as defined above is directly connected to oxygen atom, forexample: —OC(═O)-alkyl, —OC(═O)-aryl, —OC(═O)-aralkyl, —OC(═O)-aralkyl,specifically, such as acetoxy, propionyloxy, butyryloxy, isobutyryloxy,benzoyloxy, etc.

“Mono-substituted amino”, when used alone or in combination with othergroups, represents substituted or unsubstituted C1-C6 alkyl, aminosubstituted with aryl or aralkyl, for example, methylamido, ethylamido,n-propylamido, n-butylamido, n-pentylamido, anilino, etc., which can befurther substituted.

“Disubstituted amino”, when used alone or in combination with othergroups, represents amino substituted by two groups that may be the sameor different, and the substituents are selected from substituted orunsubstituted: (C1-C6) alkane, aryl or arylalkyl, such as dimethylamino,methylethylamino, diethylamino, phenylmethylamino, diphenylamino, etc.,which may be further substituted.

“Acylamido”, when used alone or in combination with other groups,represents aminocarbonyl with the general formula —C(═O)—N(group)2,mono- or di-substituted aminoacyl as defined above, for example:N-methylacylamido, N,N-dimethylamide, N-ethylamide,N-ethyl-N-phenylamide, N,N-diphenylamide.

“Acylamino”, when used alone or in combination with other groups, meansthat acyl as defined above is connected to amino. For example, it can beCH₃CONH—, C₂H₅CONH—, C₃H₇CONH—, C₄H₉CONH—, C₆H₅CONH—, etc., which may besubstituted.

“MW” and “microwave” refer to the microwave technology used in theexperiment. The type of the microwave reactor used in the experiment is“CEM Discover SP”.

As used herein, a compound or chemical moiety being described with“substituted” means that at least one hydrogen atom of the compound orchemical moiety is replaced by a second chemical moiety. Non-limitingexamples of substituents are those present in the exemplary compoundsand embodiments as disclosed herein, deuterium, fluorine, chlorine,bromine, iodine; hydroxyl, oxo; amino (primary, secondary, tertiary),imino, nitro, nitroso; cyano, isocyano, alkyl, heteroalkyl, cycloalkyl,heterocycloalkyl, aryl, heteroaryl, alkenyl, cycloalkenyl, alkynyl;lower alkoxy, aryloxy; mercapto, thioether; phosphine; carboxyl,sulfonato, phosphono; acyl, thiocarbonyl, sulfonyl; amide, sulfonamide;ketone; aldehyde; ester, sulfonate; haloalkyl (for example,difluoromethyl, trifluoromethyl); monocyclic or fused or non-fusedpolycyclic carbocycloalkyl (for example, cyclopropyl, cyclobutyl,cyclopentyl or cyclohexyl); or monocyclic or fused or non-fusedpolycyclic heterocycloalkyl (for example, pyrrolidinyl, piperidinyl,piperazinyl, morpholinyl or thiazinyl); or a monocyclic or fused ornon-fused polycyclic carbocyclic or heterocyclic aryl (e.g., phenyl,naphthyl, thiazolyl, oxazolyl, imidazolyl, isoxazolyl, pyrrolyl,pyrazolyl, triazolyl, tetrazolyl, thienyl, furyl, pyridyl, pyrimidinyl,pyrazinyl, pyridazinyl, indolyl, quinolinyl, isoquinolinyl,quinoxalinyl, bipyridyl, acridinyl, phenanthridinyl, phenanthrolinyl,quinazolonyl, benzimidazolyl, benzofuranyl, benzothienyl,benzothiazolyl, benzoxazolyl, benzisoxazolyl); or aryl-lower alkyl;—CHO; —CO (alkyl); —CO (aryl); —CO₂ (alkyl); —CO₂ (aryl); —CONH₂;—SO₂NH₂; —OCH₂CONH₂; —OCHF₂; —OCF₃; —CF₃; —NH₂; —NH(alkyl); —N(alkyl)₂;—NH(aryl); —N(alkylxaryl); —N(aryl)₂. In addition, when the substituentis oxygen, it means that two hydrogen atoms on the same or differentcarbons are substituted by the same oxygen atom to form a carbonyl orcyclic ether, such as ketone carbonyl, aldehyde carbonyl, estercarbonyl, amide carbonyl, ethylene oxide, etc. In addition, these partscan also be optionally substituted by fused ring structures or bridges(for example, —OCH₂O—). In the present invention, they can preferably besubstituted by one, two, three, four, five or six substituents which areindependently selected from halogen, alkyl, alkoxy, aryl, aryloxy, and—N(aryl)2, or substituted by perhalogen, such as trifluoromethyl,perfluorophenyl. When the substituents contain hydrogen, thesesubstituents may be optionally further substituted by substituentsselected from such groups.

As used herein, a compound or chemical moiety being described with“independently” should be understood that the multiple compounds orchemical moieties defined before the term should all mutually withoutinterference and equally enjoy the range of options provided thereafter,and should not be understood to limit any spatial connectionrelationship between the various groups; the spatial connectionrelationship is expressed by terms such as “mutually independent” and“connected” herein; it should be distinguished; moreover, in thisdisclosure, “be independently” and “be respectively independently” and“be respectively independently selected from” have basically the samemeaning.

As used herein, the description that two “adjacent” chemical moietiesbeing connected to form a ring structure should be understood to includetwo situations where two chemical moieties are adjacent in position andadjacent in space. Being adjacent in position exemplarily includes thesituation where two groups on the same aromatic ring are in the orthoposition, and being adjacent in space exemplarily includes the situationwhere two groups are respectively located on different connected orcondensed aromatic rings but can be close to each other in space.

In this application, “singlet state” is sometimes referred to as the“single state”, and correspondingly, “triplet state” is sometimesreferred to as the “triple state”.

In order to facilitate understanding and avoid confusion, in thisapplication, “Structure of Formula (III)” represents the structuralformula numbered m, and “Gold(III)” or “Au(III)” both represent metallicgold with a valence state of +3.

Unless otherwise specified, the “OLED” in this application refers toorganic light-emitting diodes. Therefore, in this application, “OLED” issometimes referred to as “OLED apparatus” or “OLED light-emittingapparatus” or “OLED device” or “OLED light emitting device”.

In addition, in order to make the present invention clear and easy tounderstand, the English names corresponding to the chemicalabbreviations involved in the specification or examples is provided,which are specifically as follows:

ACN represents acetonitrile; DMF represents N,N-dimethylformamide; DMArepresents N,N-dimethylacetamide; THF represents tetrahydrofuran; DMSOrepresents N,N-dimethylsulfoxide; TFA represents trifluoroacetic acid;TfOH represents trifluoromethanesulfonic acid; TsOH representsp-toluenesulfonic acid; AcOH represents ethanoic acid, also calledacetic acid; Pd(dba)₂ represents palladium(0) bis(dibenzylideneacetone);KOAc represents potassium acetate; Pd(dppf)Cl₂ represents[1,1′-bis(diphenylphosphino)ferrocene] palladium(II) dichloride;Pd(PPh₃)₄ represents tetrakis(triphenylphosphine) palladium(0); Binaprepresents (f)-2,2′-Bis-(diphenylphosphino)-1,1′-binaphthyl; KOtBurepresents potassium tert-butoxide; TCTA represents4,4′,4″-tris(carbazol-9-yl) triphenylamine; TAPC represents4,4′-cyclohexylbis(N,N-bis(4-methylphenyl)aniline); TPBi represents1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene; TmPyPb represents3,3′-[5′-[3-(3-pyridyl)phenyl][1,1′:3′,1″-terphenyl]-3,3″-diyl]bipyridine;HAT-CN represents2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene; T2T represents2,4,6-Tris(1,1′-biphenyl)-1,3,5-triazine; ITO represents indium tinoxide.

In order to further illustrate the present invention, the complexesprovided in the present invention are described in detail below inconjunction with examples, but they should not be understood as limitingthe protection scope of the present invention. Unless otherwisespecified, all percentages involved in the examples are by weight andall solvent mixture ratios are by volume.

Preparation of Ligand Compounds and their Precursors

Example 1—Preparation of L1

Precursor 111 (2.65 g, 9.00 mmol), precursor 112 (5.04 g, 9.90 mmol),excess ammonium acetate NHOAc and AcOH were added to a reaction flask.The resulting mixture was refluxed for 12 hours and then cooled to roomtemperature. The crude product was extracted with dichloromethane. Theorganic layer was washed with water for several times to remove excessacid. The collected organic layer was dried with anhydrous magnesiumsulfate. After evaporation to dryness, the crude product was purified bycolumn chromatography on silica gel using DCM/hexane (v:v=1:6) aseluents and 2.86 g of pure L1 was obtained with a yield of 55%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.06 (d, J=8.5 Hz, 2H), 7.89 (d, J=1.5 Hz,1H), 7.78 (d, J=1.5 Hz, 1H), 7.71 (d, J=8.5 Hz, 2H), 7.65 (d, J=2.5 Hz,2H), 7.52 (d, J=8.5 Hz, 2H), 7.37 (t, J=8.0 Hz, 4H), 7.14 (t, J-=7.5 Hz,2H), 7.10 (d, J-=8.0 Hz, 4H), 7.05 (d, J-=9.0 Hz, 2H), 6.72 (t, J=2.5Hz, 1H), 3.87 (s, 3H), 1.37 (s, 9H). ¹³C NMR (100 MHz, CD_(Z)Cl₂): b δ161.05, 159.17, 157.60, 157.37, 156.15, 152.80, 150.06, 143.23, 131.25,130.27, 128.69, 127.05, 126.03, 123.97, 119.31, 117.08, 116.67, 114.87,112.92, 110.26, 55.77, 35.00, 31.45. EI-MS: m/z 577.2584 [M]⁺.

Among them, precursor 111 and the precursor 112 can be preparedaccording to the following synthetic routes based on conventionalreaction conditions.

Example 2—Preparation of L2

The synthesis was similar to the preparation of Li. Precursor 211 (5.31g, 10.51 mmol), precursor 212 (4.68 g, 11.57 mmol), excess ammoniumacetate NH₄OAc and AcOH were added to a reaction flask. The mixture wasrefluxed for 12 hours and then cooled to room temperature. The crudeproduct was extracted with dichloromethane. The organic layer was washedwith water for several times to remove excess acetic acid. The collectedorganic layer was dried with anhydrous magnesium sulfate. Afterevaporation to dryness, the crude product was purified by columnchromatography on silica gel using DCM/hexane (v:v=1:6) as eluents and3.23 g of pure L2 was obtained with a yield of 45%. ¹H NMR (500 MHz,CD₂Cl₂): δ 8.15 (d, J=8.5 Hz, 2H), 8.01 (s, 1H), 7.94 (s, 1H), 7.76 (d,J=2.0 Hz, 2H), 7.71-7.68 (m, 3H), 7.66 (d, J=1.5 Hz, 2H), 7.45 (t, J=8.0Hz, 4H), 7.24-7.21 (m, 6H), 6.81 (t, J=2.0 Hz, 2H), 1.52 (s, 8H). ¹³CNMR (125 MHz, CD₂Cl₂): δ 159.57, 157.24, 156.42, 156.36, 152.36, 142.85,138.73, 138.70, 132.26, 130.37, 129.12, 124.26, 123.98, 123.89, 122.06,119.98, 119.73, 118.36, 118.07, 112.52, 110.09, 35.48, 31.82. EI-MS: m/z681.2187 [M]⁺.

Among them, precursor 211 and the precursor 212 can be preparedaccording to the following synthetic routes based on conventionalreaction conditions.

Example 3—Preparation of L3

A mixture of acetophenone (1.23 g, 10.25 mmol), KOtBu (2.30 g, 20.50mmol) and anhydrous tetrahydrofuran was added into a reaction flask andstirred for 2 hours at room temperature under argon. The mixture wasstirred for another 12 hours when a dry tetrahydrofuran solution ofprecursor 311 (2.89 g, 10.25 mmol) was transferred to the mixture by acannula. Then the resulting mixture was added with excess ammoniumacetate NH₄OAc and acetic acid AcOH and heated to reflux for 12 hours.After the reaction, the mixture was cooled to room temperature andextracted with water/dichloromethane. The organic layer was washed withwater for several times to remove excess acetic acid. After dried withanhydrous magnesium sulfate, the organic layer was removed of solventusing a rotary evaporator to obtain a crude product, which was purifiedby SiO₂ column chromatography (dichloromethane/hexane=1:6). 2.04 g ofpure L3 was obtained with a yield of 59%. ¹H NMR (500 MHz, CD₂Cl₂): δ8.09-8.07 (m, 2H), 7.83 (t, J=7.5 Hz, 1H), 7.74 (dd, J=8.0, 0.5 Hz, 1H),7.50-7.46 (m, 2H), 7.44-7.41 (m, 1H), 7.37-7.32 (m, 3H), 7.30 (d, J=8.5Hz, 1H), 7.18 (d, J=2.5 Hz, 1H), 7.08 (tt, J=7.0, 1.5 Hz, 1H), 7.07-7.04(m, 2H), 6.99 (dd, J=8.5, 2.5 Hz, 1H), 2.44 (s, 3H). ¹³C NMR (125 MHz,CD₂Cl₂): δ 159.45, 158.08, 156.72, 155.45, 142.36, 139.76, 137.55,132.51, 131.67, 130.13, 129.37, 129.08, 127.27, 123.42, 122.76, 120.71,119.25, 118.90, 118.72, 20.09. EI-MS: m/z 337.1446 [M]⁺.

Among them, precursor 311 can be prepared according to the followingsynthetic routes based on conventional reaction conditions.

Example 4—Preparation of precursor 421

The synthesis was similar to the preparation of L3. A mixture ofacetophenone (1.54 g, 12.79 mmol), KOtBu (2.87 g, 25.60 mmol) andanhydrous tetrahydrofuran was added to a reaction flask and stirred foraround 2 hours at room temperature under argon. An anhydroustetrahydrofuran solution of precursor 411 (3.43 g, 12.79 mmol) was addedto the mixture which was then stirred for another 12 hours at roomtemperature. Then, the resulting mixture was added with excess ammoniumacetate NH₄OAc and acetic acid AcOH and refluxed for 12 hours. After thereaction, the mixture was cooled to room temperature and extracted withwater/dichloromethane. The organic layer was washed with water forseveral times to remove excess acetic acid. After dried with anhydrousmagnesium sulfate, the organic layer was removed of solvent using arotary evaporator. The crude product was purified through SiO₂ columnchromatography (dichloromethane/hexane=1:6). 2.57 g of pure L421 wasobtained with a yield of 62%. ¹H NMR (500 MHz, CD₂Cl₂): δ 8.11 (d, J=7.5Hz, 2H), 7.85 (d, J=8.0 Hz, 1H), 7.74 (t, J=8.0, 1H), 7.67 (d, J=2.5 Hz,1H), 7.55-7.44 (m, 4H), 7.36 (d, J=7.5 Hz, 1H), 7.23 (d, J=8.0 Hz, 1H),2.42 (s, 3H). ¹³C NMR (125 MHz, CD₂Cl₂): δ 158.55, 157.02, 142.95,139.86, 139.63, 137.97, 137.60, 135.71, 132.75, 131.38, 129.44, 129.09,127.28, 122.75, 118.96, 20.33. EI-MS: m/z 323.0275 [M]+.

Among them, precursor 411 can be prepared according to the followingsynthetic route based on conventional reaction conditions.

Example 5—Preparation of Precursor 441

A mixture of precursor 421 (2.57 g, 7.93 mmol), KOAc (2.33 g, 23.79mmol), Pd(dppf)Cl₂ (0.58 g, 0.79 mmol), bis(pinacolato)diboron (4.03 g,15.86 mmol) and anhydrous 1,4-dioxane was refluxed for 24 hours and thenwas cooled to room temperature. After evaporation to dryness, themixture was extracted with water/dichloromethane. The organic layer wascollected, dried with anhydrous magnesium sulfate and then removed ofsolvent using a rotary evaporator to obtain a crude product. 1.62 g ofpure precursor 431 was obtained through SiO₂ column chromatography(dichloromethane/hexane=1:6) with a yield of 55%. ¹H NMR (500 MHz,CD₂Cl₂): δ 8.14 (d, J=7.5 Hz, 2H), 7.95 (s, 1H), 7.83 (q, J=7.5, 2H),7.74 (d, J=8.0 Hz, 1H), 7.52 (t, J=7.5 Hz, 2H), 7.46 (d, J-=7.5 Hz, 1H),7.41 (t, J=7.0 Hz, 2H), 2.54 (s, 3H). ¹³C NMR (125 MHz, CD₂Cl₂): δ160.25, 156.67, 140.66, 140.05, 139.94, 137.47, 136.50, 134.97, 130.77,129.33, 129.09, 127.33, 122.90, 118.51, 84.16, 83.64, 25.20, 21.13.EI-MS: m/z 371.2031 [M]⁺.

Precursor 431 was dissolved in tetrahydrofuran (THF), and the mixturewas placed in an ice bath. Hydrogen peroxide (H₂O₂, 30 wt % in water)was added to the THF solution and the resulting mixture was stirred atroom temperature. The progress of the reaction was detected by TLC.After the reaction, the mixture was removed of THF using a rotaryevaporator. The crude product was extracted with water/dichloromethane.The organic layer was washed with water for several times to removeexcess hydrogen peroxide, dried with anhydrous magnesium sulfate, andthen removed of solvent using a rotary evaporator. 1.00 g of precursor441 was obtained with a yield of 88%. ¹H NMR (500 MHz, CD₂Cl₂): δ 8.07(d, J=7.5 Hz, 2H), 7.83 (t, J=8.0 Hz, 1H), 7.72 (dd, J-=8.0, 0.5, 1H),7.51-7.43 (m, 3H), 7.32 (d, J=7.5 Hz, 1H), 7.11 (d, J=8.0 Hz, 1H), 6.89(d, J=3.0 Hz, 1H), 6.71 (dd, J=8.5, 3.0 Hz, 1H), 3.81 (s, 1H), 2.34 (s,3H). ¹³C NMR (125 MHz, CD₂Cl₂): δ 160.05, 157.04, 154.60, 141.40,139.73, 137.65, 132.04, 129.37, 129.06, 127.71, 127.50, 122.98, 119.14,117.24, 116.00, 19.69. EI-MS: m/z 261.1130 [M].

Example 6—Preparation of L4

A mixture of precursor 441 (1.00 g, 3.83 mmol), CuI (0.07 g, 0.38 mmol),Cs₂CO₃ (3.74 g, 11.49 mmol), N,N-dimethylglycine (0.08 g, 0.76 mmol) andanhydrous 1,4-dioxane was added into a reaction flask and refluxed for24 hours. After the reaction, the mixture was cooled to room temperatureand removed of solvent with a rotary evaporator. The resulting mixturewas extracted with water/dichloromethane. The organic layer was driedwith anhydrous magnesium sulfate and then removed of solvent with arotary evaporator to obtain a crude product, which was purified throughSiO₂ column chromatography (dichloromethane/hexane=1:5). 0.99 g of pureLA was obtained with a yield of 62%. ¹H NMR (300 MHz, CD₂Cl₂): δ8.18-8.14 (m, 2H), 7.83 (t, J=7.5 Hz, 1H), 7.77 (dd, J=7.8, 0.9 Hz, 1H),7.57-7.44 (m, 3H), 7.41-7.36 (m, 2H), 7.32-7.20 (m, 4H), 7.09-7.03 (m,2H), 2.53 (s, 3H). ¹³C NMR (100 MHz, CD₂Cl₂): δ 159.20, 159.12, 156.69,154.49, 142.52, 139.63, 137.54, 132.76, 132.49, 131.31, 129.41, 129.09,127.26, 126.23, 123.18, 122.72, 121.61, 121.26, 119.73, 118.73, 117.28,20.28. EI-MS: m/z 415.0537[M].

Example 7—Preparation of precursor 511

An anhydrous tetrahydrofuran solution of2-bromo-4,4″-di-tert-butyl-1,1′-biphenyl (3.47 g, 10.05 mmol) was cooledto −78° C. and stirred for 5 minutes under argon. After the addition ofn-butyllithium (2.4 M in THF; 4.6 ml, 11.06 mmol), the mixture wasstirred for another 2 hours at −78° C. An anhydrous tetrahydrofuransolution of precursor 511 (2.63 g, 10.05 mmol) was added into theresulting mixture which was then stirred at −78° C. for 30 minutes. Themixture was warmed to room temperature and then stirred for another 16hours. After the reaction, a saturated ammonium chloride aqueoussolution was added into the mixture which was then stirred at roomtemperature for around 20 minutes. The mixture was removed of solventusing a rotary evaporator and extracted with water/dichloromethane. Theorganic layer was collected, dried with anhydrous magnesium sulfate, andremoved of solvent using a rotary evaporator. The obtained product wasdissolved in a mixed system (concentrated sulfuric acid: aceticanhydride: glacial acetic acid=2.5 ml: 2.5 ml: 45 ml), and then themixture was stirred at 300° C. for around 7 hours. After the reaction,the mixture was cooled to room temperature and poured into ice methanol(150 ml). The precipitate obtained by filtration was washed twice withice methanol, and then the obtained precipitate was dissolved indichloromethane. The resulting solution was washed with water until thepH of the water layer was close to neutral. The organic layer wascollected, dried with anhydrous magnesium sulfate, and then removed ofsolvent using a rotary evaporator. 3.12 g of pure precursor 521 wasobtained with a yield of 61%. ¹H NMR (400 MHz, CD₂Cl₂): δ 7.69-7.66 (m,4H), 7.45 (dd, J=8.0, 1.8 Hz, 2H), 7.38-7.32 (m, 2H), 7.27-7.22 (m, 3H),7.06 (dd, J=6.6, 1.8 Hz, 1H), 7.03-7.00 (m, 2H), 1.32 (s, 18H). ¹³C NMR(125 MHz, CD₂Cl₂): δ 165.77, 151.28, 149.15, 146.59, 142.13, 139.11,138.19, 128.74, 128.01, 126.93, 126.58, 125.46, 124.32, 120.42, 119.76,67.18, 35.32, 31.65. EI-MS: m/z 494.1468[M]+.

Among them, precursor 511 can be prepared according to the followingsynthetic routes based on conventional reaction conditions.

Example 8—Preparation of L5

A mixture of precursor 521 (3.00 g, 5.88 mmol),3,5-diphenylphenylboronic acid (2.42 g, 8.82 mmol), K₂CO₃ (2.44 g, 17.64mmol), Pd(PPh₃)₄ (0.68 g, 0.59 mmol) and a mixed solvent ofwater/toluene (v:v=1:8) was refluxed for 24 hours under argon. After thereaction, the mixture was cooled to room temperature and removed ofsolvent with a rotary evaporator. The resulting mixture was extractedwith water/dichloromethane. The organic layer was collected, dried withanhydrous magnesium sulfate and then removed of solvent with a rotaryevaporator to obtain a crude product, which was purified through SiO₂column chromatography (dichloromethane/hexane=1:5). 0.99 g of pure L5was obtained with a yield of 65%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.14 (d, J=1.5 Hz, 2H), 7.83 (t, J=2.0 Hz,1H), 7.75 (d, J=8.0 Hz, 1H), 7.71 (d, J=8.0 Hz, 2H), 7.69-7.64 (m, 7H),7.48 (t, J=7.5 Hz, 4H), 7.44 (dd, J=8.0, 2.0 Hz, 2H), 7.40 (tt, J=7.0,1.5 Hz, 2H), 7.26-7.16 (m, 5H), 7.13 (d, J=7.5 Hz, 1H), 1.25 (s, 18H).¹³C NMR (125 MHz, CD₂Cl₂): δ 164.65, 156.57, 151.00, 150.38, 146.90,142.47, 141.40, 140.99, 138.38, 137.53, 129.20, 128.44, 128.42, 127.92,127.71, 126.86, 126.61, 125.18, 125.03, 124.18, 120.83, 119.68, 118.75,68.00, 35.23, 31.67. EI-MS: m/z 659.3541 [M]+.

In addition, according to the preparation/detailed synthetic protocolsof ligands L1-L5 shown in Examples 1-9, the following ligands can alsobe prepared based on the given procedures and their detailed synthesisare not shown on here.

Preparation of a Gold(III) Complex Supported by Tetradentate Ligand

As shown in the following synthetic route, there are two protocols forpreparing tetradentate gold(III) complexes (0-I). Tetradentate gold(III)complexes (0-I) can be prepared using cyclometallated gold(III)complexes (0-II) as precursors through C—H (carbon-hydrogen) bondactivation and intramolecular Au—C(gold-carbon) bond coupling reactionwith the assistance of microwave energy. Tetradentate gold(III)complexes (0-I) can also be prepared using ligands (0-III) as precursorsthrough microwave-assisted C—H bond activation and intermolecularcoordination coupling reaction between the ligand and Au(III) reagent.Precursor 0-II can be obtained through the transmetallation from thecorresponding organomercury(II) complexes which can be synthesized basedon the reaction between ligand (0-III) and Hg(II) Reagent. In addition,the coordination anion (X_(a)) of precursor (0-II) can be changed viaconventional methods.

When tetradentate gold(III) complexes are substituted with large orsensitive substituents on the core structure, such as NR¹⁷R¹⁸,tetradentate gold(III) complexes having halogen at the same positionwere prepared as precursors based on the microwave-assisted method shownin the present invention. The targeted amino-substituted tetradentategold(III) complex was then synthesized through the cross-couplingreaction between the halogen-substituted tetradentate complex and amine.That is, a versatile class of tetradentate gold(III) complexes can beprepared using tetradentate gold(III) complexes bearing differentfunctional groups for further reactions as precursors. Therefore, thepreparation of tetradentate gold(III) complexes provided by the presentinvention can realize the construction of tetradentate gold(III)complexes with different structures and emission properties. Examiple9-L1-Au(III)Cl

A mixture of Li (2.00 g, 3.46 mmol), Hg(OAc)₂ (1.43 g, 4.50 mmol) andEtOH (45 ml) was refluxed for 48 hours. Then, LiCl (0.73 g, 17.30 mmol)was added into the mixture and the resulting mixture was refluxed foranother 2 hours. After the reaction, the mixture was cooled to roomtemperature. The precipitate was collected by filtration, washed twicewith ethanol, and dried under vacuum. The obtained white solid L1-HgCl(1.57 g, 1.93 mmol, yield 56%) was used for the next step withoutfurther purification. A mixture of L1-HgCl, KAuCl₄ (0.80 g, 2.12 mmol)and acetonitrile (35 ml) was refluxed for 48 hours. After the reaction,the mixture was cooled to room temperature. The yellow solid wascollected by filtration, washed with acetonitrile twice, and dried undervacuum. 0.84 g of L1-AuCl (1.04 mmol) as yellow solid was obtained witha yield of 54%.

The above-mentioned preparation of cyclometallated gold(III) chloridesin this example is based on the literature [K-H. Wong, K-K Cheung, MC-W.Chan, C.-M. Che, Organometallics 1998, 17, 3505-3505]. The L1-Au(III)Clobtained through filtration can be used directly in the next reactionwithout further purification.

Example 10—L1-Au(III)OCOCF₃

A mixture of L1-Au(III)Cl (0.84 g, 1.04 mmol), AgOCOCF₃ (0.25 g, 1.14mmol) and dichloromethane (45 ml) was stirred for around 16 hours indark. After the reaction, the filtrate was collected through filtrationwith Celite. After evaporation to dryness, the crude productL1-Au(III)OCOCF₃ was obtained.

The preparation method in this example is based on the literature [D.-A.Rosca, D A Smith, M. Bochmann, Chem. Commun. 2012, 48, 7247-7249]. Theprepared crude product L1-Au(III) OCOCF₃ can be used directly in thenext reaction without further purification.

Example 11—Preparation of Complex 1

In a 10 ml microwave reaction tube, L1-Au(III)Cl (25 mg, 0.03 mmol) wasdissolved in a mixed solvent of ACN/H₂O (v:v=1:1, total 3 ml). Themixture was stirred for 20 min at 120° C. with the use of microwave.After the reaction, water was added into the mixture. Dichloromethanewas added into the mixture for the extraction of crude product. Thecollected organic layer was dried with anhydrous magnesium sulfate. Theproduct was purified through SiO₂ column chromatography(dichloromethane/hexane). 3.6 mg of pure complex 1 was obtained with ayield of 15%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.48 (dd, J=7.5, 1.5 Hz, 1H), 8.22 (d, J=2.0Hz, 1H), 7.82-7.80 (m, 2H), 7.74 (d, J=9.0 Hz, 2H), 7.65 (d, J=1.5 Hz,1H), 7.45-7.38 (m, 5H), 7.28 (d, J=2.0 Hz, 1H), 7.18-7.15 (m, 2H), 7.12(d, J=8.0 Hz, 2H), 7.08 (d, J=9.0 Hz, 2H), 7.00 (d, J=2.5 Hz, 1H), 3.90(s, 3H), 1.45 (s, 9H). ¹³C NMR (125 MHz, CD₂Cl₂): δ 170.29, 163.99,162.25, 161.71, 158.40, 157.94, 154.32, 154.21, 151.41, 151.28, 149.96,149.62, 136.45, 134.70, 132.35, 130.49, 130.26, 129.29, 128.52, 126.22,124.06, 123.99, 122.78, 119.45, 118.44, 116.87, 115.25, 115.10, 114.81,112.16, 109.48, 35.97, 31.74, 30.30. ESI-MS: m/z 772.2111 [M+H]⁺.Elemental analysis calculated for C₄₀H₃₂AuNO₃+0.5CH₂Cl₂: C, 59.75; H,4.09; N, 1.72; found: C, 59.63; H, 4.09; N, 1.72.

Example 12—Preparation of Complex 1

In a 10 ml microwave reaction tube, L1-Au(III)OCOCF₃ (28 mg, 0.032 mmol)was dissolved in a mixed solvent system of ACN/H₂O (v:v=1:1, total 3.2ml). The mixture was stirred for 20 min at 120° C. with the use ofmicrowave. After the reaction, water was added to the system anddichloromethane was added to extract the crude product. The collectedorganic layer was dried with anhydrous magnesium sulfate. 22.0 mg ofpure complex 1 (yield: 90%) was obtained through column chromatographyon silica gel using dichloromethane and hexane as eluents.

Example 13—Preparation of Complex 2

L2-Au(III)OCOCF₃ was prepared according to the method used forsynthesizing L1-Au(III)OCOCF₃ in examples 9-10. In a 10 ml microwavereaction tube, L2-Au(III)OCOCF₃ (280 mg, 0.282 mmol) was dissolved in amixed solvent of ACN/H₂O (v:v=1:1, total 16 ml). The mixture was stirredfor 20 min at 120° C. in a microwave. After the reaction, water wasadded to the mixture and dichloromethane was added to extract the crudeproduct. The collected organic layer was dried with anhydrous magnesiumsulfate. The product was purified through SiO₂ column chromatography(dichloromethane/hexane). 220 mg of pure complex 2 was obtained with ayield of 89%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.29 (dd, J=7.5, 1.5 Hz, 1H), 8.23 (d, J=2.0Hz, 1H), 7.78 (s, 1H), 7.75 (d, J=8.5 Hz, 1H), 7.70 (s, 1H), 7.65 (s,1H), 7.55 (d, J=1.5 Hz, 2H), 7.48 (dd, J=8.5, 2.0 Hz, 1H), 7.42-7.37 (m,4H), 7.32 (d, J=2.0 Hz, 1H), 7.19-7.11 (m, 4H), 6.96 (d, J=2.0 Hz, 1H),1.42 (s, 18H). ESI-MS: m/z 876.1737 [M+H]⁺. Elemental analysiscalculated for C₄₃H₃₇AuBrNO₂: C, 58.91; H, 4.25; N, 1.60; found: C,59.08; H, 4.52; N, 1.55.

For complex L2-Au(III)OCOCF₃, ¹⁹F NMR (376 MHz, CD₂Cl₂): δ −73.16

Example 14—Preparation of Complexes 3-4

Complex 3: A mixture of complex 2 (35 mg, 0.04 mmol), Pd(dba)₂ (9.2 mg,0.008 mmol), Binap (5.0 mg, 0.008 mmol), KOtBu (13.4 mg, 0.12 mmol) wasrefluxed in toluene for 24 hours under argon. After the reaction, themixture was cooled to room temperature. Water was added to the mixtureand dichloromethane was added to extract the crude product. Thecollected organic layer was dried with anhydrous magnesium sulfate. Theproduct was purified through SiO₂ column chromatography(dichloromethane/hexane). 17 mg of pure complex 3 was obtained with ayield of 45%.

¹H NMR (500 MHz, CD₂Cl₂): δ 7.83 (dd, J=8.0, 2.0 Hz, 1H), 7.72-7.69 (m,2H), 7.65 (d, J=1.5 Hz, 1H), 7.62 (t, J=2.0 Hz, 1H), 7.55-7.53 (m, 3H),7.40-7.36 (m, 6H), 7.32 (dd, J=8.0, 1.5 Hz, 1H), 7.29-7.24 (m, 6H),7.20-7.13 (m, 3H), 7.11-7.09 (m, 2H), 6.96 (dd, J=8.0, 2.0 Hz, 1H), 6.92(d, J=2.0 Hz, 1H), 6.74-6.71 (m, 1H), 1.41 (s, 18H). ¹³C NMR (125 MHz,CD₂Cl₂): δ 171.38, 163.57, 161.41, 158.31, 157.60, 156.04, 152.48,151.45, 151.07, 150.44, 149.61, 147.57, 144.18, 138.07, 135.72, 134.14,130.29, 129.89, 128.18, 127.39, 127.35, 126.41, 124.81, 124.50, 123.93,122.41, 122.00, 119.25, 118.34, 118.06, 116.45, 115.78, 114.87, 112.04,109.00, 35.44, 31.62. ESI-MS: m/z 965.3333 [M+H]⁺. Elemental analysiscalculated for C₅₅H₄₇AuN₂O₂: C, 68.46; H, 4.91; N, 2.90; found: C,68.46; H, 4.91; N, 2.85.

Complex 4: A mixture of complex 2 (90 mg, 0.10 mmol), Pd(dba)₂ (23.7 mg,0.021 mmol), Binap (12.8 mg, 0.021 mmol), KOtBu (33.7 mg, 0.30 mmol) wasrefluxed in toluene for 24 hours under argon. After the reaction, themixture was cooled to room temperature. Water was added to the mixtureand dichloromethane was added to extract the crude product. Thecollected organic layer was dried with anhydrous magnesium sulfate. Theproduct was purified through SiO₂ column chromatography(dichloromethane/hexane). 30 mg of pure complex 4 was obtained with ayield of 40%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.23 (dd, J=7.5, 1.5 Hz, 1H), 8.05 (d, J=2.0Hz, 1H), 8.01 (d, J=8.0 Hz, 1H), 7.79 (s, 1H), 7.67-7.65 (m, 2H), 7.58(d, J=2.0 Hz, 2H), 7.40-7.27 (m, 6H), 7.16 (t, J-=7.5 Hz, 1H), 7.07-7.02(m, 3H), 6.86 (d, J=2.0 Hz, 1H), 6.70-6.60 (m, 6H), 6.16 (dd, J=8.0, 1.5Hz, 2H), 1.44 (s, 18H). ¹³C NMR (125 MHz, CD₂Cl₂): δ 173.98, 162.69,161.56, 158.61, 157.23, 156.62, 152.63, 152.08, 151.08, 150.81, 149.28,144.44, 141.09, 137.85, 137.17, 135.86, 134.78, 132.66, 130.36, 128.75,128.69, 128.53, 125.07, 124.19, 123.74, 122.89, 122.14, 121.66, 119.53,118.15, 117.03, 116.54, 115.71, 115.69, 113.88, 112.19, 108.91, 35.50,31.65. ESI-MS: m/z 978.3072 [M]⁺. Elemental analysis calculated forC₅₅H₄₅AuN₂O₃+MeOH: C, 66.53; H, 4.89; N, 2.77; found: C, 66.77; H, 4.68;N, 2.84.

It is worth noting that the following complexes with otheramino-substituents can also be prepared using the method shown inExample 14 with the use of complex 2 as precursor.

Example 15—Preparation of Complex 5

L3-Au(III)OCOCF₃ was prepared according to the method for synthesizingL1-Au(III)OCOCF₃ in examples 9-10. In a 10 ml microwave reaction tube,L3-Au(III)OCOCF₃ (27 mg, 0.042 mmol) was dissolved in a mixed solvent ofACN/H₂O (v:v=1:1, total 3 ml). The mixture was stirred for 20 min at120° C. in a microwave. After the reaction, water was added to themixture and dichloromethane was added to extract the crude product. Thecollected organic layer was dried with anhydrous magnesium sulfate andremoved of solvent using a rotary evaporator. The product was purifiedthrough SiO₂ column chromatography (dichloromethane/hexane). 20 mg ofpure complex 5 was obtained with a yield of 89%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.35 (dd, J=7.5, 1.5 Hz, 1H), 8.06 (d, J=7.0Hz, 1H), 7.83 (t, J=8.0 Hz, 1H), 7.75 (d, J=8.0 Hz, 1H), 7.71 (d, J=7.0Hz, 1H), 7.59 (d, J=8.0 Hz, 1H), 7.49 (td, J=7.0, 1.0 Hz, 1H), 7.43-7.36(m, 2H), 7.30 (td, J=7.5, 1.0 Hz, 1H), 7.21 (d, J=8.0 Hz, 1H), 7.14-7.11(m, 1H), 7.08 (d, J=8.0 Hz, 1H), 2.64 (s, 3H). ¹³C NMR (100 MHz, CDCl₃):δ 171.02, 164.55, 163.06, 152.05, 149.55, 148.42, 148.32, 141.58,140.04, 136.50, 135.21, 133.51, 132.80, 131.10, 128.39, 126.77, 126.33,122.38, 121.40, 118.93, 117.87, 117.58, 117.26, 22.91. EI-MS: m/z531.0901 [M]⁺. Elemental analysis calculated for C₂₄H₁₆AuNO: C, 54.25;H, 3.04; N, 2.64; found: C, 54.14; H, 2.87; N, 2.66.

Example 16—Preparation of Complex 5

In a 10 ml microwave reaction tube, ligand L3 (28 mg, 0.08 mmol),Au(OAc)₃ (0.03 g, 0.09 mmol) and sodium trifluoroacetate (0.05 g, 0.36mmol) were mixed in acetic acid/H₂O (v:v=1:1, total 3 ml). The mixturewas stirred for 30 min at 150° C. in a microwave. After the reaction,the mixture was cooled to room temperature. Water was added to thesystem, and dichloromethane was added to extract the crude product. Theorganic layer was washed with water 2-3 times until the pH value of thewater layer was close to neutral. The organic layer was dried withanhydrous magnesium sulfate and removed of solvent under vacuum. Theresulting mixture was directly dissolved in a mixed solvent of ACN/H₂O(v:v=1:1, total 10 ml). Then, the mixture was stirred for 70 min at 140°C. in a microwave. After the reaction, the mixture was cooled to roomtemperature. Water was added to the system, and dichloromethane wasadded to extract the crude product. The collected organic layer wasdried with anhydrous magnesium sulfate, and then removed of solventusing a rotary evaporator. Complex 5 was purified through columnchromatography on silica gel using dichloromethane and hexane aseluents. 14 mg of pure product was obtained with a yield of 33%.

Example 17—Preparation of Complex 6

L4-Au(III)OCOCF₃ was prepared according to the method used to synthesizeL1-Au(III)OCOCF₃ in examples 9-10. In a 10 ml microwave reaction tube,L4-Au(III)OCOCF₃ (20 mg, 0.028 mmol) was dissolved in a mixed solvent ofACN/H₂O (v:v=1:1, total 2 ml). The mixture was stirred for 20 min at115° C. in a microwave. After the reaction, water was added to themixture and dichloromethane was added to extract the crude product. Thecollected organic layer was dried with anhydrous magnesium sulfate andremoved of solvent using a rotary evaporator. The product was purifiedthrough silica gel column chromatography (dichloromethane/hexane). 16 mgof pure complex 6 was obtained with a yield of 92%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.22 (dd, J=8.0, 2.0 Hz, 1H), 8.00 (d, J=7.0Hz, 1H), 7.92 (td, J=8.0, 2.5 Hz, 1H), 7.83 (dd, J=8.5, 3.0 Hz, 1H),7.76 (d, J=7.5 Hz, 1H), 7.66 (dd, J=8.0, 2.5 Hz, 1H), 7.57 (s, 1H), 7.51(t, J=7.0 Hz, 1H), 7.33 (t, J=7.5 Hz, 1H), 7.24-7.22 (m, 2H), 7.14 (d,J=8.5 Hz, 1H), 2.70 (s, 3H). ESI-MS: m/z 610.0039 [M+H]⁺. Elementalanalysis calculated for C₂₄H₁₅AuBrNO+H₂O: C, 45.88; H, 2.73; N, 2.23;found: C, 46.24; H, 2.56; N, 2.28.

For L4-Au(III)OCOCF₃, ¹⁹F NMR (376 MHz, CD2Cl2): δ −73.07.

Example 18—Preparation of Complexes 7 and 8

Preparation of complex 7: A mixture of complex 6 (90 mg, 0.15 mmol)diphenylamine (76.2 mg, 0.45 mmol), Pd(dba)₂ (17.3 mg, 0.03 mmol), Binap(37.4 mg, 0.06 mmol) and KOtBu (50.5 mg, 0.45 mmol) was heated to refluxin toluene (35 ml) for 24 hours. After the reaction, the mixture wascooled to room temperature. Water was added to the system, anddichloromethane was added to extract the crude product. The organiclayer was collected and dried with anhydrous magnesium sulfate. The puretarget was purified through column chromatography on silica gel usingdichloromethane and hexane as eluents. 44 mg of pure complex 7 wasobtained with a yield of 43%. ¹H NMR (500 MHz, CD₂Cl₂): δ 8.25 (d, J=8.0Hz, 1H), 8.07 (d, J=7.5 Hz, 1H), 7.94 (t, J=8.0 Hz, 1H), 7.87 (d, J=8.0Hz, 1H), 7.78 (d, J=7.5 Hz, 1H), 7.70 (d, J=8.0 Hz, 1H), 7.49 (t, J=7.5Hz, 1H), 7.33-7.28 (m, 5H), 7.17 (d, J=7.0 Hz, 5H), 7.13 (d, J=8.5 Hz,1H), 7.10 (d, J=2.5 Hz, 1H), 7.06 (t, J=7.5 Hz, 2H), 6.86 (dd, J=8.5,2.5 Hz, 1H), 2.72 (s, 3H). ESI-MS: m/z 699.1661 [M+H]⁺. Elementalanalysis calculated for C₃₆H₂₅AuN₂O: C, 61.90; H, 3.61; N, 4.01; found:C, 61.71; H, 3.61; N, 4.10.

Preparation of complex 8: A mixture of complex 6 (150 mg, 0.25 mmol) andphenoxazine (137.4 mg, 0.75 mmol), Pd(dba)₂ (14.4 mg, 0.025 mmol), Binap(31.1 mg, 0.05 mmol), and KOtBu (84.2 mg, 0.75 mmol) was heated toreflux in toluene for 24 hours. After the reaction, the mixture wascooled to room temperature. Water was added to the system, anddichloromethane was added to extract the crude product. The organiclayer was collected and dried with anhydrous magnesium sulfate. The puretarget was purified through column chromatography on silica gel usingdichloromethane and hexane as eluents. 82 mg of pure complex 8 wasobtained with a yield of 47%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.61 (d, J=8.0 Hz, 1H), 8.13 (dd, J=7.0, 1.0Hz, 1H), 7.97 (t, J=8.0 Hz, 1H), 7.90 (d, J=8.0 Hz, 1H), 7.81 (dd,J=8.0, 1.0 Hz, 1H), 7.73 (d, J=7.5 Hz, 1H), 7.55 (td, J=7.0, 1.0 Hz,1H), 7.42 (d, J=2.5 Hz, 1H), 7.36 (td, J=7.5, 1.0 Hz, 1H), 7.29 (d,J=8.5 Hz, 1H), 7.19 (d, J=8.5 Hz, 1H), 7.10 (dd, J=8.0, 2.5 Hz, 1H),6.70-6.60 (m, 6H), 6.11 (dd, J=7.5, 2.0 Hz, 2H), 2.75 (s, 3H). ESI-MS:m/z 712.1395 [M]⁺. Elemental analysis calculated for C₃₆H₂₃AuN₂O₂+H₂O:C, 59.19; H, 3.45; N, 3.83; found: C, 59.18; H, 3.27; N, 3.92.

It is worth noting that the following complexes with different aminosubstituents can also be prepared using the same or similar method as inExample 18 with the use of complex 6 as precursor.

Similarly, based on the synthetic protocols shown in example 9 toexample 18, other gold(III) complexes supported by the same or similartetradentate ligand frameworks or substituted with differentsubstituents can also be prepared.

Example 19—Preparation of Complex 9

In a 35 ml microwave reaction tube, ligand L5 (35 mg, 0.05 mmol) andAu(OAc)₃ (0.02 g, 0.06 mmol) were mixed in a mixed solvent of TFA/H₂O(v:v=1:1, total 12 ml). The mixture was stirred for 30 min at 130° C. ina microwave. After the reaction, the mixture was cooled to roomtemperature. Water was added to the system and dichloromethane was addedto extract the crude product. The organic layer was washed with water2-3 times until the pH of the water layer was close to neutral. Theorganic layer was dried with anhydrous magnesium sulfate and removed oforganic solvent using a rotary evaporator. The resulting mixture wasdissolved in a mixed solvent of ACN/H₂O (v:v=1:1, total 12 ml). Then,the mixture was stirred for 80 min at 140° C. in a microwave. After thereaction, the mixture was cooled to room temperature. Water was added tothe system and dichloromethane was added to extract the crude product.The organic layer was dried with anhydrous magnesium sulfate, and thenremoved of organic solvent using a rotary evaporator. The target waspurified through column chromatography on silica gel usingdichloromethane and hexane as eluents. 24 mg of pure complex 9 wasobtained with a yield of 32%.

¹H NMR (500 MHz, CD₂Cl₂): δ 8.29 (d, J=7.0 Hz, 1H), 8.06 (s, 2H), 7.93(d, J=7.5 Hz, 1H), 7.83 (d, J=8.0 Hz, 1H), 7.76 (s, 1H), 7.72-7.68 (m,6H), 7.65 (d, J=7.5 Hz, 1H), 7.51 (t, J=7.5 Hz, 2H), 7.46 (dd, J=8.0,1.5 Hz, 2H), 7.40 (t, J=7.5 Hz, 1H), 7.33 (t, J=7.5 Hz, 1H), 7.25-7.22(m, 2H), 7.01-6.97 (m, 2H), 6.93-6.89 (m, 1H), 1.25 (s, 18H). ¹³C NMR(125 MHz, CD₂Cl₂): δ 181.80, 169.29, 166.53, 162.47, 158.63, 152.28,151.71, 149.77, 148.35, 143.99, 143.25, 142.35, 141.72, 141.55, 138.65,138.14, 135.12, 129.25, 128.21, 127.80, 127.71, 127.34, 126.74, 126.06,125.66, 124.81, 122.88, 122.79, 122.02, 121.39, 120.30, 119.59, 75.37,35.46, 31.60. ESI-MS: m/z 854.3043 [M+H]⁺. Elemental analysis calculatedfor C₅₀H₄₂AuN: C, 70.33; H, 4.96; N, 1.64; found: C, 70.25; H, 5.27; N,1.64.

Example 20—Preparation of Complex 9

In a 35 ml microwave reaction tube, ligand L5 (35 mg, 0.05 mmol),Au(OAc)₃ (0.02 g, 0.06 mmol) and sodium trifluoroacetate (0.04 g, 0.29mmol) were mixed in mixed solvent of AcOH/H₂O (v:v=2:1, total 12 ml).The mixture was stirred for 25 min at 170° C. in a microwave. After thereaction, the mixture was cooled to room temperature. Water was added tothe system, and dichloromethane was added to extract the crudeprecursor. The organic layer was collected and then washed with water2-3 times until the pH of the water layer was close to neutral. Theorganic layer was dried with anhydrous magnesium sulfate and removed oforganic solvent using a rotary evaporator. Then, the resulting mixturewas dissolved in a mixed solvent of ACN/H₂O (v:v=1:2, total 12 ml) andthen was stirred for 80 min at 130° C. in a microwave. After thereaction, the mixture was cooled to room temperature. Water was added tothe system and dichloromethane was added to extract the crude product.The collected organic layer was dried with anhydrous magnesium sulfate,and then removed of organic solvent using a rotary evaporator. Thetarget was purified through column chromatography on silica gel usingdichloromethane and hexane as eluents. 29 mg of pure complex 9 wasobtained with a yield of 39%.

Similarly, based on the synthetic protocols of gold(III) complexessupported by the same or similar ligand frameworks or substituted withdifferent substituents, other gold(III) complexes supported by thesimilar tetradentate frameworks can also be prepared, as shown in thefollowing:

Example 21—Photophysical Properties of Complexes 1-8

Measurement of UV-Vis absorption spectra: the complex was dissolved inthe solvent at a concentration of 2×10⁻⁵ mol/L. After deoxygenation ofthe complex solution, the absorption spectrum of the complex wasmeasured at room temperature using the machine “Hewlett-Packard 8453diode array spectrophotometer”. Measurement of emission spectra:emission spectra recorded in four different media, in which conditions1)-3) were all measured with the instrument “Horiba Fluorolog-3spectrophotometer”. 1) Solution-state emission: the complex wasdissolved in the solvent at a concentration of 2×10⁻⁵ mol/L. Afterdeoxygenation of the complex solution, the emission spectrum of thecomplex in solution was measured at room temperature. 2) Solid-stateemission: the solid of the complex was put in a quartz tube with aninner diameter of 4 mm. The solid-state emission spectra of the complexwere measured at both room temperature and 77 K (in liquid nitrogen). 3)Glassy-state emission: a very small amount of the complex was dissolvedin a mixed solvent (ethanol/methanol/dichloromethane=4:1:1, solventvolume ratio), and the prepared solution was placed into a quartz tubewith an inner diameter of 4 mm. The emission spectrum of glassy-stateemission was measured at 77 K (in liquid nitrogen). 4) The complex andPMMA were dissolved in chlorobenzene to obtain a transparent solutionwith a mass fraction of 4 wt % of the complex. 50 μL of the solution wasdropped on a quartz plate with a size of 1 cm×1 cm×0.1 cm. It was driedat 80° C. and a transparent quartz plate containing 4 wt % of thecomplex in PMMA was obtained. The emission of the complex in PMMA thinfilm was measured at room temperature using the instrument “HamamatsuC11347 Quantaurus-QY Absolute PL quantum yields measurement system”.Measurement of emission lifetime (τ): emission lifetimes were measuredusing the instrument “Quanta Ray GCR 150-10 pulsed Nd:YAG laser system”.

The results are shown in FIG. 2-8 . FIG. 2 shows, in an embodiment ofthe present invention, the absorption spectra of (a) complexes 1 and 2and (b) complexes 5 and 6 in deoxygenated toluene solution (the complexconcentration is 2×10−5 mol/L) at room temperature; FIG. 3 shows, in anembodiment of the present invention, the absorption spectra of (a)complex 3, (b) complex 4, (c) complex 7, and (d) complex (8) indifferent deoxygenated solvents (the complex concentration is 2×10⁻⁵mol/L) at room temperature; FIG. 4 shows, in an embodiment of thepresent invention, the emission spectra of (a) complexes 1-4 and (b)complexes 5-8 in deoxygenated toluene (the complex concentration is2×10⁻⁵ mol/L) at room temperature, the emission spectra of (c) complex 4in deoxygenated/aerated toluene at a concentration of 2×10⁻⁵ mol/L atroom temperature (the asterisk “*” represents the second-ordertransmission of the excitation wavelength of 380 nm); FIG. 5 shows, inan embodiment of the present invention, the emission spectra of (a)complex 3, (b) complex 4, (c) complex 7, and (d) complex (8) indifferent deoxygenated solvents (the complex concentration is 2×10⁻⁵mol/L) at room temperature; FIG. 6 shows, in an embodiment of thepresent invention, the emission spectra of (a) complexes 1-4 and (b)complexes 5-8 in PMMA thin films (4 wt % of the Au(III) complex doped inPMMA) at room temperature; FIG. 7 shows, in an embodiment of the presentinvention, the absorption (a) and emission (b) spectra of complex 9 indeoxygenated dichloromethane (the complex concentration is 2×10⁻⁵ mol/L)at room temperature, and emission spectrum (c) of complex 9 in PMMA thinfilm (4 wt % of the complex doped in PMMA) at room temperature; FIG. 8shows the TGA thermograms of complexes 3 and 4 in an embodiment of thepresent invention, in which (a) complex 3 shows 2 wt % weight loss at394° C. and (b) complex 4 shows 2 wt % weight loss at 429° C.; FIG. 2and FIG. 3 shows that in toluene, complexes 1-8 show intense absorptionbands at 300-330 nm [ε=(1-4)×10⁴ dm³mol⁻¹cm⁻¹], and moderately intenseabsorption bands at 380-400 nm [ε=(5-29)×10³ dm³mol⁻¹dm⁻¹]. Forcomplexes 3, 4, 7 and 8, broad and weak absorption bands at 420-500 nmwere also observed. These broad and weak absorption bands are ascribedto the intralig and charge transfer transition (¹ILCT) from π(diphenylamine or phenoxazine) to π* (C{circumflex over ( )}C{circumflexover ( )}N{circumflex over ( )}C ligand).

As shown in FIG. 3 , the absorption spectra of complexes 3, 4, 7 and 8are almost insensitive to solvent polarity with negligible changes inspectral shifts but minor changes in absorption intensity.

As shown in FIG. 4 , complexes 1-8 exhibit three different types ofemission profiles: complexes 1-2 and 5-6 display vibronic emission bandswith emission quantum yields of up to 54% and emission lifetimes of upto 225 μs. Their radiative decay rate constants (k_(r)) are small,ranging from 1.2×10³ to 5.8×10³ s⁻¹. Therefore, supported by largeStokes shift, vibronic-structured emission bands and small radiativedecay rate constants k_(r) (˜10³ s⁻¹), the emission of complexes 1-2 and5-6 is assigned as phosphorescence stemming from metal-perturbedintraligand π to π* transitions (³IL) of the [C{circumflex over( )}C{circumflex over ( )}N{circumflex over ( )}C] ligand; on the otherhand, the comparison made in complexes 2, 3, 4 or complexes 5, 6 orcomplexes 7, 8 shows that these complexes have similar C{circumflex over( )}C{circumflex over ( )}N{circumflex over ( )}C framework but theyshow completely different emission properties. Complexes 3, 4, 7, and 8show structureless, broad emission bands with relatively large radiativedecay rate constants. That means that the introduction of amino groupschanges emission properties. For complex 3, the emission is sensitivetowards solvent polarity with red-shifted emission maxima from 550 nm intoluene to 570 nm in 1,2-dichlorobenzene, suggesting the emissiveexcited state with significant charge transfer character. Together withfeatureless broad emission bands, long emission lifetimes and moderateradiative decay rate, the emission of 3 is derived from ³ILCT[π(diphenylamine) to π*(C{circumflex over ( )}C{circumflex over( )}N{circumflex over ( )}C)] excited state. Taking complex 4 as anexample, the solvent is changed from toluene to 1,2-dichlorobenzene andthe emission maximum is red-shifted by 66 nm, indicating that itsemissive excited state also has significant charge transfer character.The emission of complex 4 was also collected in deoxygenated toluene andaerated toluene. As shown in FIG. 4(c), the emission intensity inaerated condition is much lower than that in degassed toluene,indicating that triplet excited states are involved in the emissionmechanism. Together with broad emission bands, short emission lifetimes(shorter than 1 μs) and relatively large radiative decay rate k_(r), theemission of complex 4 is assigned as thermally activated delayedfluorescence (TADF) originating from the intraligand charge transfertransition (¹ILCT) [π (N-substituent)→π* (C{circumflex over( )}C{circumflex over ( )}N{circumflex over ( )}C ligand)].

Gold(III) complexes supported by amino-substituted tetradentate ligandshown in the present invention display short emission lifetimes and³ELCTor thermally activated delayed fluorescence (TADF) emission properties.

Photophysical properties of complexes 1-8 at room temperature were shownin Table 1 below.

TABLE 1 Emission In degassed 4 wt % in PMMA Absorption toluene thin filmIn degassed toluene λ_(em) [nm] λ_(em) [nm] λ_(abs) [nm] (Φ, τ [μs];k_(r) [10³ (Φ, τ [μs]; k_(r) [10³ Complex (e [×10³ mol⁻¹ dm³cm⁻¹])^([a]) s⁻¹])^([b]) s⁻¹])^([c]) 1 317 (15.16), 331 (14.20), 381495, 526, 565 492, 523, 560 (5.21) (0.54; 93.07; 5.80) (0.20; 43.77;4.57) 2 315 (12.75), 381 (5.60) 498, 526, 567 490, 522, 562 (0.40;77.11; 5.19) (0.04; 90.06; 0.44) 3 302 (38.73), 382 (29.02), 456 (br,524, 550 550 12.29) (0.77; 94.34; 8.16) (0.47; 56.81; 8.27) 4 311(37.04), 380 (13.35), 465 (br, 612 570 2.07)^([a]) (0.47; 0.62; 758.06)(0.62; 1.82; 340.66) 5 304 (8.09), 379 (5.89), 394 (5.00) 493, 521 489,519, 555 (0.28; 225.18; 1.24) (0.056; 147; 0.38) 6 300(8.53), 378(5.70), 390 (4.75) 485, 518, 552 486, 518, 555 (0.26; 152.21; 1.71)(0.06; 90.38; 0.66) 7 301 (37.06), 380(13.26), 393 533 523 (12.32), 424(br, 6.68) 10.94; 1.61; 583.85) (0.45; 3.43; 131.20) 8 303 (19.28), 325(13.88), 378 580 568 (10.98), 391 (9.21), 422 (br, 1.16) (0.74; 0.79;936.71) (0.27; 1.06; 254.72) ^([a])ε was measured when the concentrationof complexes 1-8 in deoxygenated toluene was 2 × 10⁻⁵ mol/L,^([b])emission quantum yields (Φ) of complexes 1-8 were measured indegassed toluene (the complex concentration was 2 × 10⁻⁵ mol/L) usingHamamatsu C11347 Quantaurus-QY Absolute PL photoluminescence absolutequantum yield measurement system; τ refers to emission lifetime; k_(r)represents radiative decay rate constant, ^([c])emission quantum yieldof thin-film samples (containing 4 wt % tetradentate Au(III) complexes)was measured using Hamamatsu C11347 Quantaurus-QY Absolute PLphotoluminescence absolute quantum yield measurement system.

2) the absorption of complex 9 in deoxygenated dichloromethane at aconcentration of 2×10⁻⁵ mol/L was shown on here: absorption maxima withcorresponding absorption coefficient ε [×10³ mol⁻¹ dm³ cm⁻¹] 269(57.08), 282 (50.48), 304 (22.33), 335 (9.24), 359 (4.99), 389 (2.52).The emission maxima of complex 9 in deoxygenated dichloromethane at aconcentration of 2×10⁻⁵ mol/L locate at 483, 515, 555 nm.

3) The solvent effect on emission of complexes 3, 4, 7, and 8 (indifferent solvents) is shown in FIG. 5 . Photophysical properties ofcomplexes 3 and 4 are shown in Table 2 below.

TABLE 2 Emission k_(r) k_(nr) Com- λ_(max) τ ϕ [s⁻¹] × [s⁻¹] × plexMedium [nm] [μs] [%] 10⁵ 10⁵ 3 Toluene 524,550 94.34 77 0.08 0.021,2,4-Tri- 544 50.11 66 0.13 0.07 chlorobenzene Chlorobenzene 562 41.4974 0.18 0.06 o-dichloro- 570 31.84 86 0.27 0.04 benzene 4 Toluene 6120.62 47 7.58 8.55 1,2,4-Tri- 624 0.55 46 8.36 9.82 chlorobenzeneChlorobenzene 660 0.14 11 7.86 63.57 o-dichloro- 678 0.075 5 6.67 126.67benzene

The data of complexes 7 and 8 are shown in Table 3 below.

TABLE 3 Emission k_(r) k_(nr) Com- λ_(max) τ ϕ [s⁻¹] × [s⁻¹] × plexMedium [nm] [μs] [%] 10⁵ 10⁵ 7 Toluene 533 1.61 94 5.84 9.63 1,2,4-Tri-546 0.85 87 10.24 1.53 chlorobenzene Chlorobenzene 565 0.67 87 12.991.94 o-dichloro- 580 0.57 87 15.26 2.28 benzene 8 Toluene 580 0.79 749.37 0.28 1,2,4-Tri- 606 0.65 55 8.46 0.53 chlorobenzene Chlorobenzene640 0.17 14 8.24 50.59 o-dichloro- 661 0.076 5 6.58 125.00 benzene

Example 22—General Procedure for Preparing the Device

a) A pre-patterned ITO transparent glass substrate was ultrasonicallycleaned with detergent and rinsed with deionized water, thensequentially cleaned in an ultrasonic bath of deionized water, acetoneand isopropanol, and dried for later use;

b) The dried substrate was transferred to a vacuum chamber, andsequentially deposited through thermal evaporation to obtain multiplefunctional layers with predetermined thickness in the OLED successively;and

c) Finally, LiF and Al (cathode) were sequentially deposited on theelectron transport layer film by vacuum thermal evaporation.

The measurement conditions of each parameter are:

The thickness of each material layer of vacuum deposition was monitoredin situ using a quartz oscillation film thickness meter. EL spectrum,brightness, Commission internationale de l'éclairage (CIE) andelectroluminescence efficiency were measured by Photo Research IncPR-655 or Hamamatsu photonics absolute external quantum efficiencymeasurement system. Voltage-current characteristic was measured usingKeithley 2400 power supply. All devices were characterized in anatmospheric environment under unpackaged conditions.

Example 23—Complex 4 as an Emissive Dopant in OLED

Complex 4 was used as an emissive dopant with doping concentrations of 4wt %, 8 wt % and 16 wt %. The structure of the OLED device from anode tocathode was in turn: ITO/HAT-CN (5 nm)/TAPC(50 nm)/TCTA: Complex 4(doping concentration, 10 nm)/TmPyPb (50 nm)/LiF (1.2 nm)/Al (100 nm).The corresponding OLED devices were fabricated according to the generalpreparation method provided in Example 22 and predetermined structuralcomponent parameters, wherein the detailed procedures are shown on here:

a) A pre-patterned ITO transparent glass substrate was ultrasonicallycleaned with detergent and rinsed with deionized water, thensequentially cleaned in an ultrasonic bath of deionized water, acetoneand isopropanol, and dried for later use;

b) The dried substrate was transferred to a vacuum chamber, andsequentially deposited through thermal evaporation to obtain multiplefunctional layers with predetermined thickness in the OLED successively,including: HAT-CN (hole injection layer) with a thickness of 5 nm, TAPC(hole transport layer HTL) with a thickness of 50 nm, TCTA (lightemitting layer EML) with a thickness of 10 nm which was doped with 4 wt%, 8 wt % and 16 wt % of complex 4 respectively, TmPyPb (electrontransport layer ETL) with a thickness of 50 nm;

c) Finally, LiF with a thickness of 1.2 nm (electron injection layer)and Al with a thickness of 100 nm (cathode) were sequentially depositedon the electron transport layer film by vacuum thermal evaporation toobtain the OLED devices.

It should be noted that the doping concentration=the mass of the guestmaterial/(the mass of the guest material+the mass of the hostmaterial)×100%.

Finally, the performance of the OLED device based on complex 4, such asvoltage-current characteristics, EL spectrum, luminance, efficiency andCommission internationale de l'éclairage (CIE), was measured. And thedata are shown on Table 4 and FIG. 9 .

TABLE 4 Electroluminescent properties of the 4-based devices dopantconcen- CE[cd A⁻¹]^([b]) PE[lm W⁻¹]^([c]) EQE[%]^([d]) Serial tration L1000 1000 1000 number (wt %) [cd m⁻²]^([a]) Max cd m⁻² Max cd m⁻² Max cdm⁻² CIE[(x,y)]^([e]) 1  4  7300 76.10 53.23 91.98 49.18 21.99 16.790.38, 0.56 2  8 16500 70.82 64.44 81.73 62.38 24.37 21.21 0.40, 0.55 316 22700 77.78 67.48 94.00 63.72 25.03 22.01 0.43, 0.54 ^([a])Maximumluminance; ^([b])Current efficiency; ^([c])Power efficiency;^([d])External quantum efficiency; ^([e])CIE coordinates at a luminanceof 1000 cd m⁻²; CIE refers to Commission internationale de l’éclairage.

As shown in Table 4, green electroluminescence, maximum currentefficiency of 70-80 cd A⁻¹, maximum external quantum efficiency of up to25%, external quantum efficiency of up to 22% at a luminance of 1000 cdm⁻² and efficiency roll-offs down to 12.1% have been achieved.

As increasing the doping concentration from 4% to 8%, maximum luminance,current efficiency, external quantum efficiency and efficiency roll-offswere significantly changed. Small changes were observed when the dopantconcentration was increased to 16%.

Example 24—Complex 7 as an Emissive Dopant in OLEDs (The Investigationon the Doping Concentration)

Complex 7 was used as an emissive dopant with doping concentrations of 2wt %, 4 wt % and 6 wt %. The structure of the OLED device from anode tocathode was in turn: ITO/HAT-CN (5 nm)/TAPC (40 nm)/TCTA: Complex 7 (20nm)/TmPyPb (50 nm)/LiF (1.2 nm)/Al (100 nm). With reference to Example23, the OLED devices based on complex 7 were fabricated based on thegeneral preparation method provided in Example 22 and predeterminedstructural component parameters. Finally, the performance of the OLEDdevice based on complex 7, such as voltage-current characteristics, ELspectrum, luminance, efficiency and Commission internationale del'éclairage (CIE), was measured. And the data are shown on Table 5 andFIG. 10 .

TABLE 5 Electroluminescent properties of the 7-based devices dopantconcen- CE[cd A⁻¹]^([b]) PE[lm W⁻¹]^([c]) EQE[%]^([d]) Serial tration L1000 1000 1000 number (wt %) [cd m⁻²]^([a]) Max cd m⁻² Max cd m⁻² Max cdm⁻² CIE[(x,y)]^([e]) 1 2% 5850 55.89 33.14 59.85 30.50 20.68 12.26 0.23,0.48 2 4% 11000 66.99 42.27 75.15 38.69 22.71 15.35 0.25, 0.51 3 6%13500 69.34 45.60 75.31 39.81 23.52 15.44 0.26, 0.54 ^([a])Maximumluminance; ^([b])Current efficiency; ^([c])Power efficiency;^([d])External quantum efficiency; ^([e])CIE coordinates at a luminanceof 1000 cd m⁻²; CIE refers to Commission internationale de l’éclairage.

As shown in Table 5, high-efficiency blue-green electroluminescence,maximum current efficiency of 56-70 cd A⁻¹ and maximum external quantumefficiency of up to 23% have been achieved at a lower dopingconcentration. A further increase in the doping concentration has anegligible impact on EQE, PE and CE. At a practical luminance of 1000 cdm⁻², EQE can be maintained at 12-16% in these devices.

Example 25—Complex 7 as an Emissive Dopant in OLED Devices (HTL/Co-HostMaterial/Doping Concentration)

The OLED devices shown in this example were fabricated with complex 7 asan emissive dopant, and TCTA and TPBi as co-host materials in EML. Thedoping concentration is 6 wt % and 10 wt %. The structure of the OLEDdevice from anode to cathode was in turn: ITO/HAT-CN (5 nm)/TAPC (40nm)/TCTA (10 nm)/TCTA:TPBi: Complex 7 (20 nm)/TPBi (10 nm)/TmPyPb (40nm)/LiF (1.2 nm)/Al (100 nm). With reference to Example 23, the OLEDdevices based on complex 7 were fabricated based on the generalpreparation method shown in Example 22 and predetermined structuralcomponent parameters. Finally, the performance of the OLED device basedon complex 7, such as voltage-current characteristics, EL spectrum,luminance, efficiency and Commission internationale de l'éclairage(CIE), was measured. And the data are shown on Table 6 and FIG. 11 .

TABLE 6 Electroluminescent properties of the 7-based devices dopantconcen- CE[cd A⁻¹]^([b]) PE[lm W⁻¹]^([c]) EQE[%]^([d]) Serial tration L1000 1000 1000 number (wt %) [cd m⁻²]^([a]) Max cd m⁻² Max cd m⁻² Max cdm⁻² CIE[(x,y)]^([e]) 1  6% 23520 64.20 44.62 75.33 29.55 22.34 15.410.31, 0.59 2 10% 27260 62.22 47.99 67.01 31.10 21.65 16.62 0.31, 0.59^([a])Maximum luminance; ^([b])Current efficiency; ^([c])Powerefficiency; ^([d])External quantum efficiency; ^([e])CIE coordinates ata luminance of 1000 cd m⁻²; CIE refers to Commission internationale del’éclairage.

As shown in Table 6, high-efficiency green electroluminescence, maximumcurrent efficiency of 62-64 cd A⁻¹ and maximum external quantumefficiency of up to 22% have been achieved. At a luminance of 1000 cdm⁻², external quantum efficiency can be maintained above 15%.

Example 26—Complex 8 as an Emissive Dopant in OLED Devices

Complex 8 was used as an emissive dopant with doping concentrations of 4wt %. The structure of the OLED device from anode to cathode was inturn: ITO/HAT-CN (5 nm)/TAPC (40 nm)/TCTA (10 nm)/guest material:Complex8 (4 wt %, 10 nm)/ETL (10 nm)/TmPyPb (40 nm)/LiF (1.2 nm)/Al (100 nm).With reference to Example 23, the OLED devices based on complex 8 werefabricated based on the general preparation method provided in Example22 and predetermined structural component parameters. Finally, theperformance of the OLED device based on complex 7, such asvoltage-current characteristics, EL spectrum, luminance, efficiency andCommission internationale de l'éclairage (CIE), was measured. And thedata are shown on Table 7 and FIG. 12 .

TABLE 7 Electroluminescent properties of the 8-based devices Host CE[cdA⁻¹]^([b]) PE[lm W⁻¹]^([c]) EQE[%]^([d]) Serial materials/ L 1000 10001000 number ETL [cd m⁻²]^([a]) Max cd m⁻² Max cd m⁻² Max cd m⁻²CIE[(x,y)]^([e]) 1 TCTA/T2T 12440 63.08 43.80 66.02 34.40 20.33 12.010.32, 0.56 2 (TCTA:T2T)/ 27810 40.18 35.98 36.06 21.54 12.89 11.58 0.34,0.57 T2T 3 (TCTA:TPBi)/ 29500 51.17 44.16 57.41 40.81 16.09 13.88 0.39,0.56 TPBi ^([a])Maximum luminance; ^([b])Current efficiency; ^([c])Powerefficiency; ^([d])External quantum efficiency; ^([e])CIE coordinates ata luminance of 1000 cd m⁻²; CIE refers to Commission internationale del’éclairage.

The OLED devices shown in Table 7 display high-efficiency yellow-greenelectroluminescence. At a doping concentration of 4%, the single hostmaterial (for serial number 1) and co-host material (for serial numbers2 and 3) were used in the EML of the OLEDs. Maximum current efficiencyof 40-63 cd A⁻¹ and maximum external quantum efficiency of up to 20%have been achieved in these devices. At a luminance of 1000 cd m⁻²,maximum EQE can be maintained up to 14%, indicating that different hostmaterials and structural designs have a minor effect on external quantumefficiency.

Example 27—the Investigation on Thermal Stability

The measurement of thermal stability: The thermal stability of complexes3 and 4 was examined using the instrument “TGA Q50” at a heating rate of10° C. per minute with the temperature ranging from 40° C. to 800° C.FIG. 8(a) shows the TGA thermogram of complex 3 which shows 2 wt %weight loss at 394° C.; FIG. 8(b) shows the TGA thermogram of complex 4which shows 2 wt % weight loss at 429° C. It shows that complexes 3 and4 show excellent thermal stability.

Example 28—the Investigation on Operational Lifetimes

Device Lifetime Evaluation:

The OLEDs used to evaluate the long-term stability of Au(III) complexeshave a common device structure of ITO/HAT-CN (20 nm)/PT-301 (160nm)/PT-603I (5 nm)/LPH604:Au-emitter (30 nm)/PT-74M (5 nm)/LET321: Liq(25 nm, 1:1)/Liq (1 nm)/Al (100 nm). All materials except for theAu-emitter were purchased from Lumtec. They were used as receivedwithout further purification. The OLEDs were fabricated in a Kurt J.Lesker SPECTROS vacuum deposition system and encapsulated by a200-nm-thick Al2O3thin film deposited by atomic layer deposition (ALD)technique in a Kurt J. Lesker SPECTROS ALD system. EQE values of thegold(III) complexes in the devices for lifetime evaluation were given asfollows: 16.16% for complex 4, 9.3% for complex 8 and 11.1% for thereference complex 6.

The operational lifetimes (LT₉₅, LT₅₀) of devices prepared withtetradentate gold(III) emitters 4 and 8 were measured under the aboveconditions and compared with those shown by the best-performingtridentate gold(III) emitter (complex 6 in the literature S1) under thesame device configuration for a fair comparison (Table 8). Inelectroluminescence (EL) spectra, emission maxima of 587, 543 and 581 nmwere observed in devices based on tetradentate gold(III) emitters 4, 8and the tridentate counterpart complex 6 in the literature S1,respectively. The devices of 4 and 8 exhibited operational lifetimesLT₉₅ of 1.97 and 0.27 h at their initial luminance of 10390 and 10236 cdm⁻² respectively, corresponding to estimated LT_(9S) of up to 105 h at apractical luminance of 1000 cd m⁻² and 5280 h at 100 cd m⁻², which areremarkably better (>250 times) than those of the tridentate 6-baseddevice measured in the same device structure. There are another threestudies of phosphorescent gold(III)-OLEDs based on gold(III) complexessupported by tridentate ligand reported by Yam's group for comparison,in which the devices based on them showed estimated LT₉₅ of up to 10 hat 1000 cd m⁻² and 500 h at 100 cd m^(−2[S2-S4]). Compared with theoperational lifetimes of gold(III)-OLEDs fabricated with gold(III)complexes supported by tridentate ligand, the significantly improveddevice lifetimes achieved by gold(III)-TADF complexes with tetradentateligand signify the importance of employing tetradentate ligand scaffoldin the design of stable and structurally robust Au(llI)-TADF emittersfor practical applications.

Device lifetime (operational lifetime) is generally obtained bymeasuring the OLED obtained in the vacuum-deposited method, which isused to detect the stability of the OLED device, generally expressed asLT₉₅, LT₉₀, LT₈₀, LT₅₀. LT_(X) is defined as the device operationallifetime dropped to X % of the initial luminance.

The operational lifetimes are shown in table 8.

TABLE 8 Comparison of estimated operational lifetimes ofgold(III)-OLEDs. LT₉₅/hours LT₅₀/hours Gold(III) L₀/ at 1000 at 100 at1000 at 100 Emitter cd m⁻² at L₀ cd m^(−2 [g]) cd m^(−2 [g]) at L₀ cdm^(−2 [g]) cd m^(−2 [g]) Complex 4^([a]) 10390 1.97 105 5281 120^([h])6418^([h]) 321683^([h]) Complex 8^([a]) 10236 0.27  14  706 25  1304  65337  Complex 6^([a]) in  6225  0.018     0.4     20.2    2.57   57.52884 reference S1 Complex 3    4435^([b])  0.8^([c])    10^([c])   504^([c]) 105^([b]) 1321^([b])  66208^([b]) in reference S2 Complex 1    940^([d]) 7^([d]) —  316 — — — in reference S3 Complex 7   4220^([e]) — — — — —     48^([f]) in reference S4^([a])Gold(III)-OLEDs based on tetradentate complexes 4 and 8 and thetridentate complex 6 were made in the same device configuration underour laboratory conditions. ^([b])Data taken from Table S11 in referenceS2. ^([c])Value estimated from FIG. 6 in reference S2. ^([d])Data LT₇₀taken from reference S3. ^([e])The initial luminance estimated from thedevice data based on 5 wt % complex 7 (driving current density of 20 mAcm⁻² and max. current efficiency 21.1 cd A⁻¹). ^([f])Data taken fromreference S4. ^([g]) LT₉₅/LT₅₀ at luminance of 1000 cd m⁻² and 100 cdm⁻² were respectively estimated by using the formula LT(L₁) = LT(L₀) ×(L₀/L₁)^(1.7) where L₀ refers to initial luminance and L₁ refers todesired luminance. ^([h])Data refer to operational lifetimes LT₅₃ atluminance of 10390, 1000 and 100 cd m⁻². [S1] D. Zhou, W.-P. To, Y.Kwak, Y. Cho, G. Cheng, G. S. M. Tong, C.-M. Che, Adv. Sci. 2019, 6,1802297. [S2] L.-K. Li, M.-C. Tang, S.-L. Lai, M. Ng, W.-K. Kwok, M.-Y.Chan, V. W.-W. Yam, Nat. Photonics 2019, 13, 185-191. [S3] M.-C. Tang,M.Y. Leung, S.-L. Lai, M. Ng, M.-Y. Chan, V. W.-W. Yam, J. Am. Chem.Soc. 2018, 140, 13115-13124. [S4] M.-C. Tang, W.-K. Kwok, S.-L. Lai,W.-L. Cheung, M.-Y. Chan, V. W.-W. Yam, Chem. Sci. 2019, 10, 594-605.

FIG. 13 shows the comparison of the OLED performance of tetradentategold(III)-TADF complex 4 shown in the present invention and tridentategold(III) complex 6 reported in the reference S1. a) Currentdensity-voltage curves of devices; b) EL spectra of devices; c)Luminance decay against operation time. (tetra-Au-4 and tri-Au-6 referto tetradentate gold(III)-TADF complex 4 shown in the present inventionand tridentate gold(III) complex 6 reported in the literature S1,respectively.

In summary of the above examples, it is found that complexes 1-8 showprominent emission properties, such as emission quantum yields, emissionlifetimes, and radiative decay rate constants, especially for complexes3, 4, 7 and 8 showing ³ILCT or TADF emission properties. The OLEDdevices fabricated with these complexes as emissive dopants showblue-green to green-yellow electroluminescence with high luminance,electroluminescence efficiency and maximum external quantum efficiency.Maximum current efficiency of up to 78 cd A⁻¹, maximum external quantumefficiency generally above 20% and of up to 25% and efficiency roll-offdown to 11% have been achieved. At a practical luminance of 1000 cd m⁻²,EQE can be maintained up to 11%. As is investigated by TGA, thesecomplexes are thermally stable in both air and humid environments, andshow the great potential in the development of high-efficiency OLEDs inthe market.

According to the literatures, the emission of the reported gold(III)complexes is mainly dominant by phosphorescence, and the OLEDs based onthem showed maximum EQEs of up to 21.6% (Nat. Photonics 2019, 13,185-191). These reported gold(III) emitters are different from thetetradentate gold (III)-TADF complexes shown by the present invention interms of emission origin, the structure of the chelating ligand and thecore structure of the complex. Compared to the reported gold(III)complexes, gold (III)-TADF complexes with tetradentate ligand shown inthe present invention exhibit better performance in OLEDs with maximumEQEs of up to 25.03% and EQEs of up to 22.01% at a practical luminanceof 1000 cd m⁻². Gold(III) complexes with tetradentate ligandssubstituted with different substituents at different positions canachieve or basically achieve satisfactory emission performance thatmeets the requirements of commercial applications. These are currentlythe best results achieved in OLED devices based on cyclometallatedgold(III) complexes. Therefore, the use of gold(III) complexes supportedby tetradentate ligand provided by the present invention as emissivedopants in OLED devices has outstanding advantages.

All references cited herein, including publications, patent applicationsand patents, are incorporated herein by reference to the same extent asseparately and specifically indicating that each reference isincorporated by reference and is described in its entirety herein.

The terms “a”, “an” and “the” and similar designations shall beconsidered to cover both singular and plural forms when used to describethe context of the present invention, unless otherwise specified hereinor there is an clear conflict in the context.

The ranges of values recited herein are only intended to be used asshorthand notations for individually referring to each individual valuefalling within the range, and unless otherwise indicated herein, eachindividual value is incorporated into this specification as ifindividually recited herein. Unless otherwise specified, all accuratevalues provided herein represent corresponding approximate values (forexample, all exemplary accurate values provided based on specificfactors or measurements can be considered as corresponding approximatemeasured values that are also modified by “about” as needed).

The use of any and all examples or exemplary language (eg, “forexample”) provided herein is only intended to better clarify the presentinvention and does not constitute a limitation on the scope of thepresent invention, unless otherwise indicated. The language in thisspecification should not be construed as indicating that any element isnecessary for implementing the present invention, unless it is clearlystated that it is.

When referring to elements in any aspect or embodiment of the presentinvention, descriptions using terms such as “comprising”, “having”,“including” or “containing” are intended herein to provide support forsimilar aspects or embodiments of the present invention of “consistingof” specific elements and “essentially consisting of” specific elementsor “essentially include” specific elements, unless otherwise indicatedor there is a clear conflict in the context (for example, when thecomposition described herein contains specific elements, it should beunderstood as to also describe the composition consisting of thiselement, unless otherwise indicated or there is a clear conflict in thecontext).

The above are only the preferred embodiments of the present invention.It should be pointed out that without departing from the principle ofthe present invention, those ordinary skilled in the art can makeseveral improvements and modifications, and these improvements andmodifications should also be regarded as the protection scope of thepresent invention.

1. A gold(III) complex, wherein the gold(III) complex has a chemical structure as shown in formula (I):

wherein X¹, X², X³ are independently selected from carbon and nitrogen, and only one of X¹, X², X³ is nitrogen; Y is O, CR¹⁵R¹⁶ or S; R¹-R¹⁶ are independently selected from hydrogen, deuterium, halogen, nitro, cyano, isocyano, trifluoromethyl, or independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy, heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group, acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido or trialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy and heteroaryloxy; or any two adjacent or proximal groups in R¹-R¹⁸ together with the carbon atoms they attached form a 5-15 membered ring.
 2. The gold(III) complex according to claim 1, wherein the R¹-R¹⁶ are independently selected from hydrogen, deuterium, halogen, nitro, cyano, isocyano, trifluoromethyl, or independently selected from the following substituted or unsubstituted groups: C₁₋₁₅ alkyl, C₃₋₁₈ cycloalkyl, C₂₋₁₅ alkenyl, C₃₋₁₈ cycloalkenyl, C₂₋₁₅ alkynyl, C₆₋₃₀ aryl, C₇₋₃₅ aralkyl, C₂₋₂₀ heteroalkyl, C₃₋₂₀ heterocycloalkyl, C₅₋₃₀ heterocycloalkenyl, C₅₋₃₀ heteroaryl, C₆₋₃₀ heteroaralkyl, C₁₋₂₀ alkoxy, C₆₋₃₀ aryloxy, C₅₋₃₀ heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group, acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido and trialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from the following substituted or unsubstituted groups: C₁₋₁₅ alkyl, C₃₋₁₈ cycloalkyl, C₂₋₁₅ alkenyl, C₃₋₁₈ cycloalkenyl, C₂₋₁₅ alkynyl, C₆₋₄₀ aryl, C₇₋₄₅ aralkyl, C₂₋₂₀ heteroalkyl, C₃₋₂₀ heterocycloalkyl, C₅₋₃₀ heterocycloalkenyl, C₅₋₃₀ heteroaryl, C₆₋₃₀ heteroaralkyl, C₁₋₂₀ alkoxy, C₆₋₃₀ aryloxy and C₅₋₃₀ heteroaryloxy; preferably, the NR¹⁷R¹⁸ is a group represented by the following structure or a derivative group of the group represented by the following structure in which a hydrogen is substituted by one or more, same or different substituents:

wherein, Y² is O, S, CR²⁰R²¹, SiR²²R²³ or NR²⁴, R²⁰-R²⁴ are independently selected from hydrogen, deuterium, halogen, substituted or unsubstituted C₁₋₁₅ alkyl, substituted or unsubstituted C₆₋₃₀ aryl; the substituents in the substituted derivative groups are halogen, C₁₋₂₀ alkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ alkylthio, 5-6 membered cycloalkyl, 5-6 membered heterocycloalkyl, C₆₋₃₀ aryl, C₆₋₃₀ aryloxy, C₅₋₃₀ heteroaryl, C₂₋₁₅ alkenyl, or C₂₋₁₅ alkynyl.
 3. The gold(III) complex according to claim 1, wherein the total number of carbon atoms of the groups R¹-R¹⁶ is 1-80, preferably 6-60, and more preferably 12-50.
 4. The gold(III) complex according to claim 1, wherein at least one of R¹-R¹⁶ is not hydrogen; and/or at least one of R¹-R¹⁴ is NR¹⁷R¹⁸; and/or R¹-R¹⁴ comprise 1-3 NR¹⁷R¹⁸ groups; and/or at least one of R², R³, R⁶, R⁹, R¹², and R¹³ is NR¹⁷R¹⁸.
 5. The gold(III) complex according to claim 1, wherein when R¹-R¹⁶ are groups containing substituents, the substituents on the groups are halogen, nitro, cyano, trifluoromethyl, C₁₋₂₀ alkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ alkylthio, 5-6 membered cycloalkyl, 5-6 membered heterocycloalkyl, C₆₋₃₀ aryl, C₆₋₃₀ aryloxy, C₅₋₃₀ heteroaryl, C₂₋₁₅ alkenyl or C₂₋₁₅ alkynyl.
 6. The gold(III) complex according to claim 1, wherein R¹-R¹⁶ are independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, cyano, isocyano, trifluoromethyl, ester group, acyloxy, acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido, trialkylsilyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentyloxy, n-hexoxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, vinyl, propenyl, butenyl, pentenyl, hexenyl, ethynyl, propynyl, butynyl, pentynyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, phenyl, naphthyl, anthryl, phenanthryl, fluorenyl, phenylmethyl, phenylethyl, phenylpropyl, phenoloxy, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, tert-butylphenyl, n-pentylphenyl, isopentylphenyl, neopentylphenyl, n-hexylphenyl, n-heptylphenyl, n-octylphenyl, n-nonylphenyl, n-decylphenyl, dimethylphenyl, diethylphenyl, di-n-propylphenyl, diisopropylphenyl, di-n-butylphenyl, diisobutylphenyl, di-tert-butylphenyl, di-n-pentylphenyl, di-isopentylphenyl, di-neo-pentylphenyl, di-n-hexylphenyl, di-n-heptylphenyl, di-n-octylphenyl, di-n-nonylphenyl, di-n-decylphenyl, diphenylaminophenyl, furyl, pyranyl, pyridyl, pyrimidinyl, thiazolyl, oxazolyl, imidazolyl, isoxazolyl, pyrrolyl, pyrazolyl, triazolyl, tetrazolyl, thienyl, furyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, indolyl, quinolinyl, isoquinolinyl, quinoxalinyl, bipyridyl, acridinyl, phenanthridinyl, phenanthrolinyl, quinazolonyl, benzimidazolyl, benzofuranyl, benzothienyl, benzothiazolyl, benzoxazolyl, benzisoxazolyl, pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, thiazinyl and the following structural formula:


7. The gold(III) complex according to claim 1, wherein the 5-15 membered ring formed from any two adjacent or proximal groups in R¹-R¹⁸ together with the carbon atoms they attached is 5-15 membered aromatic ring, 5-15 membered heterocyclic ring, 5-15 membered cycloalkane or 5-15 membered unsaturated cycloalkane; wherein the heteroatoms in the heterocyclic ring are independently selected from nitrogen, sulfur and oxygen.
 8. The gold(III) complex according to claim 1, wherein the gold(III) complex is specifically as follows:


9. A method for preparing a gold(Ill) complex supported by tetradentate ligand, comprising reacting the tridentate gold(III) complex of formula (0-II) under microwave conditions to obtain a gold(III) complex of formula (0-I); or reacting an organic compound of formula (0-III) with gold(III) reagent under microwave conditions to obtain a gold(III) complex of formula (0-I);

wherein X¹, X², X³ are independently selected from carbon and nitrogen, and only one of X¹, X², X³ is nitrogen; X′¹, X′², X∝³ are independently selected from CH and nitrogen, and only one of X′¹, X′², X′³ is nitrogen; Y¹ is O, CR¹⁵R¹⁶ or S; X_(a) is F, Cl, Br, I, OTf, OCOCF₃, OAc, OH, or NTf₂; R¹⁵ and R¹⁶ are independently selected from hydrogen, deuterium, halogen, nitro, cyano, isocyano, trifluoromethyl, or independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy, heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group, acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido and trialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy and heteroaryloxy; or any two adjacent or proximal groups in R¹-R¹⁸ together with the carbon atoms they attached form a 5-15 membered ring; A, B, C, and D are independently substituted or unsubstituted aromatic rings, substituted or unsubstituted heteroaromatic rings, and when the rings of A, B, C, and D contain multiple substituents, any two adjacent or proximal substituents can be linked to form a 5-15 ring.
 10. A method for preparing the gold(III) complex according to claim 1, comprising reacting the gold(III) complex of formula (II) under microwave conditions to obtain a complex of formula (I); or reacting an organic compound of formula (III) with gold(III) reagent under microwave conditions to obtain a gold(III) complex of formula (I);

wherein X¹, X², X³ are independently selected from carbon and nitrogen, and only one of X¹, X², X³ is nitrogen; X′¹, X′², X′³ are independently selected from CH and nitrogen, and only one of X′¹, X′², X′³ is nitrogen; Y¹ is O, CR¹⁵R¹⁶ or S; X_(a) is F, Cl, Br, I, OTf, OCOCF₃, OAc, OH, or NTf₂; R¹-R¹⁶ are independently selected from hydrogen, deuterium, halogen, nitro, cyano, isocyano, trifluoromethyl, or independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy, heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group, acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido and trialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy and heteroaryloxy; or any two adjacent or proximal groups in R¹-R¹⁸ together with the carbon atoms they attached form a 5-15 membered ring.
 11. The method of claim 10, wherein the reaction of the organic compound of formula (III) with gold(III) reagent is specifically: reacting the organic compound of formula (III), gold(III) reagent and a second solvent under microwave conditions to obtain an intermediate; wherein the gold(III) reagent is selected from Au(OAc)₃, AuCl₃, Au(OTf)₃, HAuCl₄, KAuCl₄, NaAuCl₄, KAuBr₄ and NaAuBr₄, preferably Au(OAc)₃; the second solvent is a mixture of one or more of water, conventional alcohol solvents, ACN, DMF, DMSO, DMA, THF and 1,4-dioxane; mixing the intermediate with a first solvent for further reaction to obtain the gold(III) complex of formula (I); wherein the first solvent is water or a mixture of water with one or more of ACN, DMF, DMA, THF and 1,4-dioxane.
 12. A tetradentate ligand having a structure of formula (III),

wherein X′¹, X′², X′³ are independently selected from CH and nitrogen, and only one of X′¹, X′², X′³ is nitrogen; Y¹ is O, CR¹⁵R¹⁶ or S; R¹-R¹⁶ are independently selected from hydrogen, deuterium, halogen, nitro, cyano, isocyano, trifluoromethyl, or independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy, heteroaryloxy, NR¹⁷R¹⁸, acyl, acylamino, acyloxy, ester group, acylamido, sulfonylamino, sulfonyloxy, sulfonato, sulfonylamido and trialkylsilyl; wherein R¹⁷ and R¹⁸ are independently selected from the following substituted or unsubstituted groups: alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, aralkyl, heteroalkyl, heterocycloalkyl, heterocycloalkenyl, heteroaryl, heteroaralkyl, alkoxy, aryloxy and heteroaryloxy; or any two adjacent or proximal groups in R¹-R¹⁸ together with the carbon atoms they attached form a 5-15 membered ring.
 13. A method for preparing light-emitting devices, comprising using the gold(III) complex according to claim
 1. 14. A light-emitting device comprising a light-emitting layer, wherein the light-emitting layer comprises the gold(III) complex according to claim
 1. 